Abstract: Disclosed is an optical recording medium, comprising a polymer alloy forming a phase-separated domain structure of a coating object, and a volatile substance interacting with the polymer alloy. The volatile substance in a vapor state is deposited on the surface of specific phase-separated domain, and dispersedly infiltrated into the phase-separated domain. The phase-separated domain and the volatile substance chemically interact with each other. The optical recording medium is operable to perform optical recording by utilizing change in the transmittance, reflectance, refractive index or surface potential thereof in response to irradiation of ultraviolet light, visible light, or infrared light from outside. The present invention can provide an optical recording medium suitable for high-density recording in a wide wavelength range.

Abstract: The present invention relates to an optical memory device and an operating process thereof. The optical memory device have a recording layer containing a photochromic compound and an electron-accepting compound which is a Lewis acid compound having a Lewis acid part and a long chain part having carbon atoms of C12 or more. One aspect of the operating process has a recording step which recording is performed on the optical memory device by irradiating visible light corresponding to the absorption band of the colored photochromic compound for recording using decolorizing, before and after recording, heating treatments are performed to control the decolorizing sensitivity of the photochromic compound, and an erasing step which ultraviolet light is irradiated to the area including the recorded portion in order to uniformly color the recording layer again.

Abstract: Methods and apparatus are provided for making an optically readable media unreadable. The method includes steps of (a) providing the media with an optically activated mechanism that degrades the reflectivity of a surface wherein information is encoded; (b) exposing the media to optical radiation for reading out the information; and, during the step of exposing, (c) initiating the operation of the optically activated mechanism. In this embodiment the step of initiating includes steps of (d) generating singlet oxygen in a layer disposed on the media; and (e) reacting the singlet oxygen with a metal-containing layer for oxidizing the surface of the metal-containing layer, thereby degrading the reflectivity of the surface. In a further aspect the optically activated mechanism causes a defocusing of a readout beam, thereby degrading reflection of the readout beam from a surface wherein information is encoded.

Abstract: An optical information memory medium, including, in the stated order a substrate, an optical information memory layer which is capable of memorizing information therein, and a reversible display recording layer which is capable of rewritably recording therein, in a visibly recognizable form, at least part of an information corresponding to the information memorized in the optical information memory layer, and a display recording method using the optical information memory medium are disclosed.

Abstract: The present invention describes a method of forming a mask comprising: providing a substrate, the substrate having a first thickness; forming a balancing layer over the substrate, the balancing layer having a second thickness; forming an absorber layer over the balancing layer, the absorber layer having a first region separated from a second region by a third region; removing the absorber layer in the first region and the second region; removing the balancing layer in the second region; and reducing the substrate in the second region to a third thickness. The present invention also describes a mask comprising: an absorber layer, the absorber layer having a first opening and a second opening, the first opening uncovering a balancing layer disposed over a substrate having a first thickness, and the second opening uncovering the substrate having a second thickness.

Abstract: A printing method is disclosed wherein a grained and anodized aluminum support is coated with an image recording layer comprising hydrophobic thermoplastic polymer particles. The heat-sensitive imaging material thus obtained is then image-wise exposed and processed, thereby obtaining a material having a lithographic image which consists of hydrophobic printing areas on a hydrophilic support and which is used as a printing master in a printing press. After the press run, the lithographic support is recycled by removing the hydrophobic printing areas from the hydrophilic surface of the aluminum support. The recycled support is then reused in a next cycle of coating, exposing, processing and printing. By using a grained and anodized aluminum support having a hydrophilic surface with a surface roughness, expressed as arithmetical mean center-line roughness Ra, which is less than 0.45 &mgr;m, the run length of the printing master is improved.

Abstract: A lithographic printing method is disclosed which comprising the steps of providing an imaging material which comprises a support and an image-recording layer that is not removable with a single-fluid ink which comprises an ink phase and a polar phase; image-wise exposure of the image-recording layer to heat or light without substantially ablating said image-recording layer, thereby switching the affinity of the image-recording towards ink or an ink-abhesive fluid and thereby creating a printing master comprising a lithographic image which consists of unexposed areas that have affinity for one phase of said ink phase and polar phase and of exposed areas that have affinity for the other phase of said ink phase and polar phase; printing, wherein the single-fluid ink is supplied to the printing master.

Abstract: There is provided improvement of a light-heat conversion in a light-stimulated writing method. An image recording body includes an element, which absorbs light (electromagnetic wave), provided in a surface of a recording body 10, or in a recording layer formed on uppermost layer of the recording body having a material exhibiting thermal changeable character of wettability, or in a substrate or an intermediate layer of the recording body. After a liquid is on the recording body 10 by a liquid forming means 3, light-stimulated writing is carried out. When the light-stimulated writing is carried out with light (electromagnetic wave) from a light (electromagnetic wave) source according to image information, an efficiency of light-heat conversion can be enhanced by a light (electromagnetic wave)-absorbing element.

Abstract: A light-reaction type optically active compound and light-reaction type chiral agent of the following general formula (I) or (II). In the general formulae, R1 and R2 represent a hydrogen atom, an alkoxy group having 1 to 15 carbon atoms, an acryloyloxyalkyloxy group having 3 to 15 carbon atoms in total or a methacryloyloxyalkyloxy group having 4 to 15 carbon atoms in total.

Abstract: The present invention relates to a diarylethene derivative and a photochromic thin film using the same. More particularly, it relates to a diarylethene derivative and a photochromic thin film having excellent transparency prepared by depositing the same on the surface of a substrate, without crystallization or agglomeration to have effective photochromic property. This method also provides homogenous thin photochromic films with film thickness of a nano meter level and improved processability compared to conventional deposition processes thus, being suitable for coloring change with light repeatedly, optical information recording systems, and optical communication media.

Abstract: Polymeric material suitable for the preparation of optical recording media for binary and/or multibit and/or volume data storage is disclosed. The molecular structure of the material contains a main chain and side chains.

Abstract: Disclosed is a reversible thermosensible recording medium comprising a base board, a rewritable thermosensible recording layer which contains a liquid crystal compound showing a cholesteric liquid crystal phase and is provided on the base board, and a protective layer which is provided on the recording layer and contains an ultraviolet curing resin and at least one of a lubricant and an ultraviolet stabilizer.

Abstract: Dye precursor molecules—normally rhodamine base—held in a transparent matrix are reactive with acids, bases, ions or radicals—and in the case of rhodamine are reactive with acids—to produce dye molecules—i.e., rhodamine—having markedly different spectroscopic properties. Light-sensitive molecules—normally a compound of ortho-nitro-aldehyde, in particular o-nitro-benzaldehyde or, preferably, 1-nitro-2-naphthaldehyde—in the same matrix undergo photochemical reaction when selectively exposed to light so as to form at least one of the acids, bases, ions or radicals with which the dye precursor molecules are reactive—preferably nitroso acid.

Abstract: There is disclosed a reversible recording material having a liquid crystal mixture comprising at least two cholesteric liquid crystal compounds. The cholesteric liquid crystal compounds which are contained in the reversible recording material has a molecular weight of less than 2000 and a grass transition temperature equal to or more than 30° C. The two cholesteric liquid crystal compounds are compatible each other. After at least a part of the reversible recording material is heated to a temperature where the part of the reversible recording material becomes a cholesteric liquid crystal phase, the part of the reversible recording material is rapidly cooled down to below the glass transition temperature thereof, so that a reflecting color from the reversible recording material can be fixed to achieve a recording.

Abstract: A method of producing a lithographic printing plate comprising a step of providing on a support a layer has a hydrophobic surface and comprises an oxidizable material and a reducible material, a step of irradiating imagewise with active rays in the presence of a photocatalytic metal compound, wherein the oxidizable material in the irradiated area is decomposed imagewise to convert the layer surface in the irradiated area surface into hydrophilic property and form an imagewise distribution of hydrophilic areas and hydrophobic areas: and a lithographic printing plate precursor used in the aforesaid method. In accordance with this method, no development-processing is required for plate-making, the plate-making operations can be carried out as the plate precursor is mounted on a printing press, and the lithographic printing plate made can have an excellent press life and hardly generates staining.

Abstract: The present invention relates to a method by which items of digital information can be stored repeatedly by light induction in a two-dimensional medium and erased again, the items of information being optically readable.

Abstract: A reversible recording medium has a support, a reversible light absorbing layer formed on the support, and, a reversible cholesteric reflection layer formed on the reversible light absorbing layer, containing a cholesteric liquid crystalline compound capable of assuming a cholesteric liquid crystalline phase reversibly showing iridescent colors by selective reflection. A method for reversibly recording an image in the above-mentioned recording medium, and a reversible recording apparatus using the above-mentioned recording medium are also disclosed.

Abstract: A three dimensional optical data storage and retrieval system that includes a three dimensional optical data storage medium and an apparatus for providing access to data stored on the medium. The data storage medium includes an optical data storage material which either a low molecular weight or polymeric glassy solid that are capable of undergoing multi-photon excitation that are energetically different in the write and read cycles. The optical data storage materials provide substantially higher storage capacities relative to conventional materials, and show high robustness in that written and stored data can undergo multiple read cycles without erasure or overwriting. An apparatus for data recording and accessing stored data on the medium includes a controllable variable energy photo-emitting excitation source and an emission photo-detector.

Abstract: The present invention is directed to styryl dyes having the formula: 1

Abstract: The present invention relates to novel compounds of the naphthopyran type which have an annelated carbocycle in position 5,6. These compounds are of formula (I) given below: in which A is an alicyclic ring which is optionally annelated with an aromatic ring and in which two adjacent R3 can together form at least one ring, for example a benzo group. These compounds (I) possess interesting photochromic properties. The invention also relates to the method of preparing these compounds (I), as well as their applications as photochromes and compositions and (co)polymer matrices comprising them.

Abstract: An optical recording film in the form of a monomolecular layer, includes chemisorptive molecules that are chemically bonded by covalent bonding to a surface of a substrate. The optical recording film has the property that, when irradiated with polarized light, a long axis orientation of the chemisorptive molecules is changed to a direction in which the polarized light is irradiated. A reflective film may be formed on the substrate surface. For the chemisorptive molecules it is possible to use CH3—COO—C6H4—(CH2)6—SiCl3, for example. The molecules undergo a dehydrochlorination with active hydrogen in the base material surface, and are chemically bonded to the base material surface by covalent bonding. Thus, an erasable or a write-once optical recording medium of high density can be provided by chemisorption without necessitating vacuum vapor deposition to form the recording layer.

Abstract: Optical data carrier comprising a preferably transparent substrate which may, if desired, have previously been coated with one or more reflection layers and to whose surface a light-writeable information layer, if desired one or more reflection layers and if desired a protective layer or a further substrate or a covering layer have been applied, which can be written on or read by means of blue, red or infrared light, preferably laser light, where the information layer comprises a light-absorbent compound and, if desired, a binder, characterized in that at least one merocyanine dye is used as light-absorbent compound.

Abstract: A holographic recording medium comprising an amorphous host material which undergoes a phase change from a first to a second thermodynamic phase in response to a temperature rise above a predetermined transition temperature; a plurality of photo-sensitive molecular units embedded in the host material and which can be orientated in response to illumination from a light source; whereby said molecular units may be so orientated when said host material is at a temperature equal to or above said transition temperature but retain a substantially fixed orientation at temperatures below said transition temperature.

Abstract: In the optical information recording medium of the present invention, a first recording layer having a translucent film and a second recording layer having a reflection film are layered. At least one layer of the first recording layer is provided, and the translucent film reversibly varies its reflectance and its transmittance according to a temperature variation caused by difference in a converging state of reproducing light. This ensures to obtain a sufficient amount of the reproducing light reflected from the first and second recording layers.

Abstract: A diarylethene compound of the following formula (1) wherein R1 is a hydrogen or a substituted or unsubstituted C1-22 alkyl group, a fluoro group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenylalkyl group, R2 is a C1-22 alkylene group which may be unsubstituted or substituted with fluorine, R3 is a chemical bond, O, S, NR1, N(R2R1), or a C1-3 alkylene group which may be unsubstituted or substituted with one or more oxygen atoms or fluorine atoms, X and Y independently of one another O, S, nitrogen, NR1, or N(R2R1), and Z is a carbonyl group or a methylene group which may be unsubstituted or substituted with fluorine.

Abstract: Cholesteric liquid crystal compositions and a recording medium which includes cholesteric liquid crystal composition are disclosed. The cholesteric liquid crystal composition has a characteristic, in a cholesteric phase, of reflecting visible light in accordance with temperature. By rapidly cooling the display from a cholesteric phase, the material can be solidified in a reflection state. The cholesteric material also has the characteristic during a transition from a solid phase to a cholesteric phase of having of an enthalpy &Dgr;Hch at a substantially constant value during a time when a temperature thereof increases during one of differential thermal analysis and differential scanning calorimetry.

Abstract: An optical information memory medium, including, in the stated order a substrate, an optical information memory layer which is capable of memorizing information therein, and a reversible display recording layer which is capable of rewritably recording therein, in a visibly recognizable form, at least part of an information corresponding to the information memorized in the optical information memory layer, and a display recording method using the optical information memory medium are disclosed.

Abstract: An optically readable media (10) has an information-encoding layer (16) and at least one color-forming layer (12) that embodies an optical readout-limiting mechanism. In a first embodiment the at least one color-forming layer contains an additive that does not interfere with the optical readability of the media for a duration of a readout period. The additive, upon exposure to a source of optical radiation that is suitable for reversing the color-forming layer from an optical readout inhibiting state to an optical readout enabling state, undergoes a transformation that maintains the color-forming layer in the optical readout inhibiting state. More specifically, exposure to the source causes the color-forming layer to photobleach and the additive to oxidize, where the oxidation of the additive permanently inhibits the optical readability of the media. The additive may be a leuco dye.

Abstract: Disclosed are a printing plate precursor having an anodized titanium film layer on a surface thereof; a process for lithography which comprises image-wise exposing the surface of the printing plate precursor to an actinic light, bringing the exposed surface into contact with a printing ink to form a printing surface where the image areas have received the ink, and using the resultant printing plate to conduct printing; and the process for lithography described above which further comprises cleaning the surface of the printing plate after completion of the printing to remove the remaining ink from the surface, subsequently heating the printing plate precursor at 80 to 500° C., and then repeatedly using the printing plate precursor.

Abstract: Disclosed is an extremely rapidly photo-addressable storage media from inherently slow photo-addressable polymers by irradiating a substrate over a large area with a light source suitable for conventional inscription so that an optical anisotropy, i.e. a double refraction with a preferential direction in the plane of the substrate occurs. If the substrates so prepared are briefly intensively irradiated, the pattern is inscribed extremely rapidly and permanently. The invention also relates to novel side-chain polymers in which high optical anisotropy can be generated by irradiation. This optical anisotropy is very heat stable.

Abstract: A method of producing a lithographic printing plate which comprises subjecting a printing plate precursor comprising a support having a metallic compound layer which has a photo-catalytic property and a hydrophilic surface and bears light-heat convertible minute particles on the surface thereof to imagewise irradiation of heat mode to convert polarity of the metallic compound layer, thereby forming an imagewise hydrophobic region. The lithographic printing plate can be repeatedly employed.

Abstract: An electrophoretic display liquid including a dispersion medium, a first granular material having one or more hollows therein and a color and a second granular material having a color different from the color of the first granular material. When an imagewise electric field is applied to the display liquid, the second granular material electrophoreses in a direction, resulting in formation of an image of the second granular material in the display liquid.

Abstract: An offset printing plate precursor comprising a substrate having provided thereon a layer containing a substance capable of absorbing radiant rays and converting the radiant energy to heat energy, and a thin layer, wherein printing is performed by following the steps of: (a) subjecting the printing plate precursor to irradiation with active light, (b) subjecting the printing plate precursor to irradiation with light/heat convertible radiant rays or heat treatment, to thereby imagewise distribute a hydrophilic area and a lipophilic area of the thin layer, and (c) bringing the thin layer into contact with printing ink to form a printing plate in which the lipophilic area has received the printing ink, to thereby perform offset printing.

Abstract: A platemaking system uses an intermediate imaging mask made of a film of photochromic material, preferably bacteriorhodopsin. The film is normally transparent, but it is temporary made opaque by exposure to light of a certain wavelength. An image is formed on the mask using light of the appropriate wavelength, which renders portions of the mask opaque. The mask is then interposed between a photosensitive printing plate and a light source which produces light to which the plate is sensitive, exposing the printing plate and thereby transferring the desired image onto the plate. The described method is preferably implemented using a transparent rotating drum that is coated with a bR film. As the drum rotates past a green or yellow laser, a desired image is written onto the film by the laser's beam. The drum rotates the image until it is opposite a photosensitive printing plate, and a light source inside the drum exposes the plate through the mask to transfer the image.

Abstract: A photosensitive material comprising a substrate and a reversibly decolorable colored layer disposed thereon, wherein the reversibly decolorable colored layer is reversibly colored and decolored, the reversibly decolorable colored layer is in a colored state at 25 ° C., and a temperature at which the color density of the reversibly decolorable colored layer is reduced to 50% based on that at 25 ° C. is 50 to 120 ° C. A method for forming an image using the photosensitive material is also provided.

Abstract: This invention provides a reversible image display medium comprising two substrates opposed to each other with a predetermined gap therebetween, one or more developer-accommodating cells formed between the two substrates, and a dry developer accommodated in each cell, in which the dry developer contains at least two kinds of frictionally chargeable dry developer particles having different chargeable polarities and different optical reflection densities, the reversible image display medium having at least any of the following features:

Abstract: Methods and apparatus are provided for making an optically readable media unreadable. The method includes steps of (a) providing the media with an optically activated mechanism that degrades the reflectivity of a surface wherein information is encoded; (b) exposing the media to optical radiation for reading out the information; and, during the step of exposing, (c) initiating the operation of the optically activated mechanism. In this embodiment the step of initiating includes steps of (d) generating singlet oxygen in a layer disposed on the media; and (e) reacting the singlet oxygen with a metal-containing layer for oxidizing the surface of the metal-containing layer, thereby degrading the reflectivity of the surface. In a further aspect the optically activated mechanism causes a defocusing of a readout beam, thereby degrading reflection of the readout beam from a surface wherein information is encoded.

Abstract: The heavily-doped silver chalcogenides, Ag2+&dgr;Se and Ag2+&dgr;Te, show magnetoresistance effects on a scale comparable to the “colossal” magnetoresistance (CMR) compounds. Hall coefficient, magnetoconductivity, and hydrostatic pressure experiments establish that elements of narrow-gap semiconductor physics apply, but both the size of the effects at room temperature and the linear field dependence down to fields of a few Oersteds are surprising new features.

Abstract: Disclosed is a reversible heat-sensitive recording material which is excellent in light resistance and is remarkably free from discoloration caused by exposure to light and erasing failure and which shows a high layer strength and has durability against repeated printing and erasing, the reversible heat-sensitive recording material having a support, a reversible heat-sensitive recording layer formed on the support and at least one protective layer formed thereon, the reversible heat-sensitive recording layer containing a normally colorless or slightly colored dye precursor and a reversible color developer capable of causing a reversible change in color density of the dye precursor on the basis of a difference in cooling rate after heating, wherein at least one of the said layers contains an isocyanate compound and an ultraviolet absorbent capable of reacting with the isocyanate compound to undergo crosslinking.

Abstract: Provided is an optical element comprising a biopolymer having an oriented structure and a photoresponsive compound, such as a photochromic compound, wherein at least a portion of the photoresponsive compound is incorporated within the oriented structure of the biopolymer and wherein the oriented structure is laminar with the planes of the laminar orientation being aligned perpendicular to a surface of the optical element. Preferably, the biopolymer is a liquid crystal polypeptide, such as ferroelectric liquid crystal poly(&ggr;-methyl-L-glutamate), and the photochromic compound is bacteriorhodopsin. Such optical elements may be utilized in a holographic grating, in an optical correlator system such as for pattern recognition, in a dynamic holographic recording system, and in an optical switch.

Abstract: The present invention relates to the field of optical recording materials, in particular, fluorescent compounds and matrices suitable for use in optical memory systems, including three dimensional optical memory systems for READ ONLY MEMORY (ROM). In particular, nonfluorescent Rhodamine B lactams are photochemically transformed into fluorescent Rhodamine B derivatives.

Abstract: Phase-change type, reversible optical information recording medium, being possible for recording, reproducing, erasing, and rewriting of information, by use of a laser beam. This invention, consists of recording thin film of ternary elements, for example, containing Ge, Te, Sb/or Bi or quaternary elements containing the fourth element of Se with which a part of Te is replaced, which is established on such surface—flat substrates as glass or plastics. In this case, the component ratio of Te and Se is selected not to be excess for other elements, such as Ge, Sb/or Bi so as to be fixed as stable compounds of stoichiometric compositions of GeTe, Sb2Te3/or Bi2Te3, or GeSe, Sb2Se3/Bi2Se3 when crystallized. Strictly speaking, a concentration of each component is selected to have proper ratio of the number of atoms each other so as to represent whole composition as the sum of each component. By this treatment, it is possible to have high crystallization speed and long cyclability of recording/erasing.

Abstract: A chemical composition is provided for the manufacture of devices for storing and/or displaying information, comprising a network having a molecule which is formed from a metallic element Fe(II) which is bonded to a 1-2-4 triazole ligand (H-Trz), which molecule further comprises one or more than one anions A selected from BF4−, ClO4−, CO32−, Br−, Cl−, in accordance with the formulation: FeII(H-Trz)3A2, characterized in that this composition is used in the pure state in either one of the two crystalline phases (&agr;,&bgr;) at least one of which, referred to as the second phase (&bgr;), can be thermally induced on the basis of the other phase, referred to as the first phase (&agr;), at a temperature which is equal to or higher than a first reference temperature (To), which phases each show thermally inducible spin transitions between a low-spin state at a low first temperature (T&agr;1, T&bgr;1) and a high-spin state at a high second temperature (T&agr;2, T&bgr;2), the spin tran

Abstract: A printer and a restoration method for a printing plate which can be reused, while coping with digitization of printing processes is provided. On a substrate serving as a hydrophilic surface mounted beforehand onto a plate cylinder, a toner image portion formed on the surface of a photosensitive material is adhered and fixed directly or via an intermediate body to thereby form an image area. In thus way, the substrate is divided into a hydrophobic image area having at least a 50° or higher contact angle with water and a non-image area having an ink repulsion property, to thereby form a printing plate. After completion of printing, the ink and wetting solution adhered to the surface of the printing plate are cleaned by a cleaning apparatus, and image area on the surface of the printing plate is then removed by a chemical treatment solution supply roller, to thereby restore the printing plate to the initial condition so that this can be reused.

Abstract: A plate precursor for a lithographic printing plate requiring no development, which comprises a surface formed of a solid material of an inorganic compound comprising at least two kinds of elements selected from groups 13, 14 and 15 of the periodic table; a method for making a lithographic printing plate using the same; and a novel plate precursor for a lithographic printing plate in which an image can be formed and deleted.

Abstract: A rewritable, heat sensitive, color image recording medium having a pair of opposed substrate sheets at least one of which is transparent, and a heat sensitive layer interposed between the substrate sheets and containing a cholesteric liquid crystal compound having a molecular weight of not greater than 2,000 and a glass transition point of at least 35° C. A color image is formed on the recording medium by varying imagewise the temperature of the heat sensitive layer from a first temperature to a second temperature such that the cholesteric liquid crystal compound assumes a cholesteric liquid crystal phase at at least one of the first and second temperatures. The image is fixed by rapidly cooling the recording medium to a temperature lower than the glass transition point of the cholesteric liquid crystal compound.

Abstract: Applications of photoerasable colorant composition include photoerasable price markings for pricing goods, documents such as gaming tickets for securely communicating concealed information, photoerasable paint for temporary markings on terrain and structures such as signs, roadways, trees, and buildings, marking instruments such as pens, and wick or felt markers, ultraviolet light exposure indicators, and dry printing. The photoerasable or mutable colorant composition comprises a mutable colorant and an ultraviolet radiation transorber which, upon irradiation with ultraviolet radiation, interacts with the colorant to irreversibly mutate the colorant and thereby render the colorant substantially colorless. The mutable colorant composition may also include a molecular includant.

Abstract: Applications of photoerasable colorant composition include photoerasable price markings for pricing goods, documents such as gaming tickets for securely communicating concealed information, photoerasable paint for temporary markings on terrain and structures such as signs, roadways, trees, and buildings, marking instruments such as pens, and wick or felt markers, ultraviolet light exposure indicators, and dry printing. The photoerasable or mutable colorant composition comprises a mutable colorant and an ultraviolet radiation transorber which, upon irradiation with ultraviolet radiation, interacts with the colorant to irreversibly mutate the colorant and thereby render the colorant substantially colorless. The mutable colorant composition may also include a molecular includant.

Abstract: The optical storage device and method includes a fluorescent layer arranged on a substrate and having a surface. The fluorescent layer is composed of fluorescent dye molecules embedded in a transparent polymeric base material. A group of data-carrying structures are arranged in the fluorescent layer. Each of the data-carrying structures has more than two optical states represented by a specific degree of quenching of fluorescence emitted from the data-carrying structure when irradiated with a fluorescence exciting radiation.

Abstract: An optical information storage material which can reversibly store said information comprising a polymeric material with a dependence of optical activity on temperature characterized in that the optical activity is substantially invariant at temperatures below Tg of said polymer, and variant at a temperatures at or near or above the Tg.