Abstract: A chemically strengthened bioactive glass-ceramic composition as defined herein. Also disclosed are methods of making and using the disclosed compositions.

Abstract: Provided are an optical glass with a high refractive index which has excellent devitrification resistance both in a molten state and during reheating, and a glass material for press molding and an optical element which are comprised of the optical glass. This optical glass includes, in mass %, 15-37% of B2O3 and SiO2 in total, 15-45% of TiO2, Nb2O5 and ZrO2 in total, and 12-40% of BaO, SrO, CaO, MgO, K2O, Na2O and Li2O in total, has a mass ratio (B2O3/(B2O3+SiO2)) of 0.15 or more, a mass ratio (TiO2/(TiO2+Nb2O5+ZrO2)) of 0.01 to 0.8, a mass ratio ((BaO+SrO+CaO)/(BaO+SrO+CaO+MgO+K2O+Na2O+Li2O)) of 0.4 or more, and a mass ratio ((K2O+Na2O+Li2O)/(BaO+SrO+CaO+MgO+K2O+Na2O+Li2O)) of 0.1 or more, substantially does not include PbO, and has a refractive index nd of 1.78-1.84, and an Abbe's number ?d of 26-32.

Abstract: Disclosed are silica and fluoride doped lead-bismuth-gallium heavy metal oxide glasses for visible to mid-wave Infrared Radiation transmitting optics and preparation thereof.

Abstract: The present invention relates to an optical element comprising: a optical glass made of a phosphate glass or a fluorophosphate glass; and an optically functional film formed on a surface of the optical glass, wherein the optically functional film comprises two or more layers made of different materials, and the outermost surface layer thereof is made of a material(s) having low reactivity with phosphoric acid.

Abstract: The space glasses have a composition, in wt. % based on oxide content, including SiO2, 12-45; B2O3, 0-4; Al2O3, 0-4; TiO2, 0-5; PbO, 50-82; Na2O, 0-4; K2O, 0-8; and at least 0.1 wt. % of a total amount of at least three doping agents selected from CeO2, MoO3, Bi2O3, WO3, Ag2O, SnO2, Sb2O3 and As2O3. Light-weight and space-saving optical systems for outer space applications can be made with these space glasses, which have high UV- and VIS-transmittance and high transmittance stability, because of their high radiation resistance based on their dopant content. A preferred process for making the space glass includes melting the above-stated oxide ingredients in a quartz crucible at 1050° C. to 1200° C. to form a melt and refining the melt at 1230° C. to 1350° C.

Abstract: The space glass has a composition, in wt. % based on oxide content, of: SiO2, 5-65; B2O3, 0-40; Al2O3, 0-12; PbO, 25-50; Na2O 0-8; K2O, 0-20; ? alkali metal oxides, at least 0.25; and at least 0.1 wt. % of a total amount of three or more doping agents selected from CeO2, MoO3, Bi2O3, WO3, Ag2O, SnO2, Sb2O3 and As2O3. In addition, it contains one or more of the following doping agents in the following amounts: at most 1 wt. %, CeO2; at most 0.02 wt. %, As2O3; at most 0.3 wt. %, Sb2O3; and at most 0.5 wt. %, SnO2. Light-weight optical systems for space are made from it, because of its high radiation resistance. A preferred process for making space glass includes melting the oxide starting ingredients at 1050° C. to 1200° C. to form a melt and refining the melt at 1230° C. to 1350° C.

Abstract: An element, particularly a transparent element, including at least one glass element, configured as a protective glass against ionizing radiation and/or UV radiation, wherein at least a portion of the surface of the glass element is covered by a film that includes a substance that can be switched into at least two states.

Abstract: Provided is a radiation-shielding glass, including a glass composition in % by mass of 10 to 35% SiO2, 55 to 80% PbO, 0 to 10% B2O3, 0 to 10% Al2O3, 0 to 10% SrO, 0 to 10% BaO, 0 to 10% Na2O, and 0 to 10% K2O, in which the radiation-shielding glass has a total light transmission at a wavelength of 400 nm at a thickness of 10 mm of 50% or higher. Also provided is a radiation-shielding glass which has the similar glass composition and can be used for a gamma-ray shielding glass for a PET examination.

Abstract: The optical glasses have increased refractive indices and are useful for making space-saving and light-weight imaging optics with lenses of different glass types for use in different objects travelling in space. The optical glasses are suitable for production of optics having low total weight, which is decisive for space applications. These space glasses have high UV- and VIS-transmittance in a range of between 300 and 800 nm and high stability of transmittance over a period of years, because their aging has been greatly limited.

Abstract: The optical glasses have increased refractive indices and are useful for making space-saving and light-weight imaging optics with lenses of different glass types for use in different objects travelling in space. The optical glasses are suitable for production of optics having low total weight, which is decisive for space applications. These space glasses have high UV- and VIS-transmittance in a range of between 300 and 800 nm and high stability of transmittance over a period of years, because their aging has been greatly limited.

Abstract: The object of the present invention is to provide an optical glass which has optical constants such as a refractive index of from 1.45 to 1.65 and an Abbe number of at least 65 and which is yet excellent in chemical durability. A phosphate optical glass comprising, as glass components by mass %, from 73 to 85 of P2O5, from 14 to 26 of Al2O3, from 1 to 12 of K2O+Li2O, from 0 to 12 of SiO2, from 0 to 12 of B2O3, from 0 to 12 of Na2O, from 0 to 12 of Y2O3, from 0 to 12 of La2O3, from 0 to 12 of MgO+CaO+SrO+BaO, from 0 to 10 of ZrO2+TiO2+Gd2O3, from 0 to 10 of Ta2O5+GeO2+Ga2O3+Nb2O5+WO3+TeO2, from 0 to 2 of Sb2O3, and from 0 to 12 of ZnO+PbO.

Abstract: A glass with high internal transmission as well as low tendency to radiation-caused physical compaction and low tendency to solarization, comprising 18 to 31% by weight of SiO2, 0 to 7% by weight of Na2O3, 0 to 7% by weight of K2O, 65 to 84% by weight of PbO, 0.001 to 1% by weight of As2O3+As2O5, which is characterized by a content of 0 to 5000 ppm of Sb2O3 0 to 500 ppm of TiO2 0 to 100 ppm of CuO 0 to 1000 ppm of F. The ?(As2O3, As2O5, Sb2O3, F)?20 ppm and the ratio of As(III)/As(V) is at least 0.5. Such a glass is suitable for the use as optical element.

Abstract: A glass for covering electrodes, which consists, as represented by mass percentage based on the following oxides, essentially of from 35 to 55% of PbO, from 15 to 30% of B2O3, from 4 to 15% of SiO2, from 20 to 44% of B2O3+SiO2, from 0.5 to 10% of TiO2+ZrO2+La2O3+Ta2O5, from 0 to 15% of Al2O3, from 0 to 25% of BaO, from 0 to 1% of CuO and from 0 to 1% of CeO2.

Abstract: The invention relates to uses of glasses and glass-ceramics in dental and orthodontic applications.

Abstract: A high-gain phosphate glass composition, which can be used to produce ultra-short gain length lasers and optical amplifiers is described wherein the composition of the glass in addition to exhibiting high gain for lasers and amplifiers, also exhibits high thermal shock resistance, high cross section, insignificant concentration quenching, and high solubility for rare earth ions and other properties which enable the material to be fabricated into a new class of ultra-short length micro-laser, fiber laser and amplifier configurations and designs.

Abstract: The present invention relates to a plasma display panel comprising transparent electrodes and a dielectric layer covering said transparent electrodes on at least one substrate of a pair of substrates facing each other with a discharge space therebetween, the main constituent of the transparent electrodes is included in the dielectric layer. Further, the main constituent of the transparent electrode is indium oxide and indium oxide is included in the dielectric layer. By including the main constituent of the transparent electrodes in the dielectric layer, it is believed that the drop in conductivity caused by diffusion of the dielectric substance in the transparent electrodes during high-temperature processing is prevented.

Abstract: Zinc-containing optical glass materials with a refractive index nd between 1.52 and 1.66, an Abbe number vd of between 35 and 54 and a composition (in % by weight based on oxide) of: SiO2 38-58, ZnO 0.3-42, PbO 0-<30, ZnO+PbO 20-55, Li2O 0-<3, Na2O 0-14, K2O 0-12, Li2O+Na2O+K2O≧2, F 0-3, MgO 0-6, CaO 0-<5, SrO 0-6, BaO 0-<0.9, B2O3 0-<1, Al2O3 0-<1.5 and ZrO2 0-<2 and, if appropriate, refining agents in the customary amounts.

Abstract: A glass for covering electrodes, which consists, as represented by mass percentage based on the following oxides, essentially of: Mass percentage PbO 44 to 68% Bi2O3 0 to 18%, B2O3 19 to 23%, SiO2 1.2 to 5%, Al2O3 2 to 6%, ZnO 4 to 9%, CuO 0.1 to 0.5%, In2O3 1.1 to 2%, SnO2 0 to 1%, and CeO2 0 to 1%.

Abstract: A low melting point glass for covering electrodes, which contains Cu in a content as calculated as CuO within a range of from 0.1 to 0.9% by mass percentage and which contains neither Mo or Sb.

Abstract: An optical glass for polarizing optical system having a photoelastic constant C in the range of −0.2 to +0.

Abstract: An optical glass comprises the following composition in mass percent of: SiO2 18-29%; PbO 68-78%; and TeO2 0.1-3.5%; wherein the glass has optical constants which are a refractive index (nd) having a range of 1.75 to 1.87 and an Abbe number (&ngr;b) having a range of 21 to 28; and a wavelength of a light transmitted through the glass having a thickness of 10±0.1 mm at a transmittance of 80% by including a reflection loss, is not more than 420 nm.

Abstract: The present invention provides a method for inducing a refractive index change in a lead silicate glass material comprising: providing a lead silicate glass material; and irradiating the lead silicate glass material to increase the index of refraction of said lead silicate glass material. The present invention also provides a photo-induced lead silicate glass grating.

Abstract: The present invention is directed at a leaded copper boroaluminosilicate glass, having coefficients of thermal expansion (CTES) of between 25-55×10−7/°C. (over a range of 25-300° C.) and a softening point in the range of 550-725° C., being suitable for use as a sealing glass, especially for borosilicate glasses, and having a composition consisting essentially, in terms of weight percent on an oxide basis, of 27-60 SiO2, 3-14 Al2O3, 9-28 B2O3, 0.0-10 R2O, 0.1-40 PbO, 0.1-11 CuO, where R2O is an alkali oxide selected from the group consisting of Li2O, Na2O, K2O, Rb2O and Cs2O.

Abstract: An optical glass for polarizing optical system having a photoelastic constant C in the range of −0.2 to +0.5 [10−8 cm2/N] with respect to a wavelength of 633 nm, the optical glass having the following composition (1): composition (1): when represented in terms of wt. % of oxides: SiO2: 17.0-27.0% (35.5-57.0 mol %) Li2O+Na2O+K2O: 0.5-5.0% (0.7-20.0 mol %) PbO: 72.0-75.0% (39.1-45.0 mol %) As2O3+Sb2O3: 0.1-3.0% (0.1-2.0 mol %).

Abstract: The invention relates to a lead silicate glass, to the use thereof for the production of secondary electron multipliers, and to a process for setting a reduced surface resistance of a lead silicate glass of this type. The lead silicate glass has the following composition (in % by weight): SiO2 15-35, PbO 35-55, Bi2O3>20-29, BaO 0-10, Cs2O 0-10, BaO+Cs2O 2-13, CaO 0-10, SrO 0-10, CaO+SrO+BaO 0-10, and up to 1% by weight of conventional fining agents. The surface resistance of the lead silicate glass after reduction in a hydrogen atmosphere is from 0.1 to 60 M&OHgr;/sq.

Abstract: A lead silicate glass frit composition particularly useful for the formation of dielectric layers and barrier ribs in plasma display panels.

Abstract: A primarily polycrystalline but partially amorphous electrical insulator can hermetically seal first and second spaced electrical terminals, one made from an anodized aluminum and the second made from a beryllium copper or Kovar or an alloy of beryllium, copper, nickel and gold. Nickel may be diffused into the beryllium copper and a noble metal may be deposited on the nickel. The insulator provides a flat meniscus to abut a corresponding electrical insulator in a cable. The insulator may provide an electrical impedance of approximately 50 ohms, an electrical resistivity greater than approximately 1018 ohms and a dielectric constant of approximately 6.3. The insulator operates satisfactorily in a frequency range to approximately 40 gigahertz.

Abstract: Provided are a glass such as a sealing glass which contains a rare earth element and crystalline particles, a structure made by sealing with said sealing glass, a magnetic head made by bonding using said sealing glass, and a magnetic recording and reproducing apparatus on which said magnetic heads are mounted. According to the glass of the present invention, magnetic heads, and other structures can be bonded at low temperatures and a high bond strength can be attained, and thus, magnetic heads having high-speed sliding properties and magnetic recording and reproducing apparatuses of high reliability can be obtained. The glass can be also used for heat resistant parts such as a pannel glass for a cathode-ray tube and the like.

Abstract: This invention relates to fluorescent photosensitive vitroceramics and the process for the production thereof. The fluorescent photosensitive vitroceramics according to the present invention employ fluorosilicate glass compositions including various photosensitizing metals and rare earths which impart photosensitive properties and fluorescent properties to the vitroceramic. After irradiation, the photosensitive agents control the precipitation of fine fluoride crystals which also contain rare earth ions. These rare earth ions can be made to fluoresce in a controlled manner. The inventive fluorescent photosensitive vitroceramics can be used in photographic applications, florescent displays and computer memories.

Abstract: A dental porcelain composition, comprising a glassy matrix and rubidium leucite crystallites embedded therein, and having maturing temperatures in the range from about 650.degree. C. to about 800.degree. C. and CTEs in the range from about 13 to about 17, more preferably in the range from about 13.5 to about 16, and most preferably in the range from about 14 to about 16.times.10.sup.-6 /.degree. C. (measured from 25.degree. C. to 400.degree. C.). The tetragonal rubidium leucite is preferably both fine-grained (i.e., having average diameters of less than about 5 microns) and uniformly sized. Preferably, the average diameters are less than about 1 to about 2 microns.

Abstract: A glass composition for a substrate with a built-in lead-dielectric material, containing up to 35 mol % calculated as Al.sub.2 O.sub.3 of aluminum oxide, 20 to 60 mol % calculated as CaO of calcium oxide, and 8 to 40 mol % calculated as SiO.sub.2 of silicon oxide.

Abstract: This invention relates to a process for preparing ceramic-like materials with specific properties by binding an inorganic filler in the form of a dry composition with a grain size of up to 25 .mu.m containing in the volume ratio 1:0.-1.52 a waste phosphogypsum and magnetite or glass-forming oxides, with an unsaturated polyester resin in an amount of 46-220 volume parts per 100 volume parts of the filler. The use of magnetite makes it poisible to prepare materials with magnetic properties, while glass-foming oxides enable preparing materials effective to absorb an X-radiation of 45-55 keV and a hard radiation of 0.6-125 MeV. When an expanding agent is added to the raw composition according to this invention, an expanded material is obtained, having completely closed pores, particularly useful in the building industry.

Abstract: A powder composition for the preparation of an opaque dental porcelain, containing as its componentsone or more feldspar frits consisting of a number of feldspar frits of different chemical compositions and different physical properties;CeO.sub.2 as the opacifier, optionally additional opacifiers; andoptionally pigments.

Abstract: A glass material for molding an optical element and including lead and a lead compound is processed chemically and physically and includes a modificative ion component set such that an atomic concentration of the modificative ion component in a range of 600 angstroms from a glass surface layer has a concentration gradient approximated by a curve represented by the following formula (1). ##EQU1## wherein, reference numeral Y designates an atomic concentration of a modificative ion shown by atomic percent. Reference numeral X designates a depth from an uppermost glass surface layer. Each of coefficients A0 to A10 is set to a constant. Symbol 0 designates a power. Reference numeral e(x) designates an error component.

Abstract: The invention relates to a glass of high refractive index suitable for the close-vision part of multifocal, in particular phototropic multifocal, spectacle lenses. The glass has a composition (in % by weight, based on oxide) of:SiO.sub.2 28-40; B.sub.2 O.sub.3 0-8.5; Li.sub.2 O 0-1; Na.sub.2 O 0-2.5; K.sub.2 O 0-5; CaO 0-6; SrO 0-6; BaO 6-12; ZnO 9-16; PbO 32-40; TiO.sub.2 0.3-7; ZrO.sub.2 0.4-5; .SIGMA. Li.sub.2 O+Na.sub.2 O+K.sub.2 O 0-5, anda refractive index n.sub.e of 1.66-1.81, an expansion coefficient .alpha..sub.20-300 of 5.7-6.8.times.10.sup.-6 K.sup.-1, a softening point of 650.degree.-700.degree. C. and a glass transition temperature Tg of 520.degree.-560.degree. C.

Abstract: A high efficiency wavelength up-conversion transparent glass ceramics composition is provided containing a rare earth ion, which can be applied to short wavelength solid lasers, full color displays, infrared light detecting sensors, etc. The ceramic composition has the following chemical composition, in which fluoride fine crystals containing rare earth ions are preferentially precipitated:______________________________________ SiO.sub.2 10-60 mol % AlO.sub.1.5 0-40 mol % GaO.sub.1.5 0-40 mol % PbF.sub.2 5-60 mol % CdF.sub.2 0-60 mol % GeO.sub.2 0-30 mol % TiO.sub.2 0-10 mol % ZrO.sub.2 0-10 mol % ReF.sub.3 or ReO.sub.1.5 0.05-30 mol % (Re = Er, Tm, Ho, Yb, Pr, etc.).

Abstract: The present invention provides new and improved dielectric materials. In one preferred embodiment such novel dielectric material is formed by firing a composition including a glass composition comprising in weight percent from about 22% to about 45% ZnO, from about 4% to about 22% MgO, from about 1% to about 16% Al.sub.2 O.sub.3, from about 20% to about 49% SiO.sub.2, from about 2% to about 11% BaO, up to about 10% ZrO.sub.2, from about 0.05% to about 1.1% Fe.sub.2 O.sub.3 and from about 0.05% to about 0.95% PbO.

Abstract: A sealing glass composition suitable for bonding ceramic surfaces at low temperatures and which includes in weight percent 5-50% thallium oxide, 10-40% vanadium oxide, 5-30% tellurium oxide, 1.5-15% arsenic oxide and 1-5% phosphorous oxide. Other additives may be included, such as bismuth oxide. A paste formulated from said glass and a filler for the purpose of adjusting the fluidity and/or dielectric constant of the paste.

Abstract: Articles formed of lead glass or crystal are treated in order to minimize the tendency for the article to leach lead or other heavy metals into products, such as alcohols or acidic foods, placed in contact therewith. In a preferred embodiment, flasks formed of glass containing between about 12% and 40% by weight lead oxide are provided with a thin layer or slip of kaolin, and heated at a temperature and for a time sufficient to exchange lead ions in the flask with ions other than lead in the kaolin layer. Preferably, the layer is applied as a thixotropic barbotin (slip) of pure hydrated aluminum silicate, and coated flasks are exposed to a temperature of between about 300.degree. C. and the strain point of the glass forming the flask and for a time ranging between about 3 and about 6 hours; rapid heating and cooling is avoided.

Abstract: Thick film paste composition for applying conductive patterns to automotive window glass comprising finely divided particles of metallic silver, glass frit having transition metal oxide, contained in the glass, all of the particulate solids being dispersed in an organic medium.

Abstract: For the production of a composite glass powder of any particle size from a fine particle size, multi-component mixture of a low-melting glass powder, fillers, and additives, the fine particle size, multicomponent mixture is sintered for 10-60 minutes at a temperature at which the base glass has a viscosity of 10.sup.5 to 10.sup.6.5 dPas, and the resultant sintered cake is ground to a powder of the desired particle size. If the multicomponent mixture comprises components decomposable with the release of gas, e.g., copper carbonate, the latter are decomposed prior to sintering at a temperature below the sintering temperature. The resultant composite glass powder containing copper oxide can be used for coating varistors.

Abstract: This invention relates to thallium tellurite glasses possessing a high Verdet constant and high optical nonlinearity, as well as good visible and infrared transmission, making them suitable materials for the fabrication of active optical devices. The glasses consist essentially, expressed in terms of cation percent, of 5-74.5% TeO.sub.2, 0.5-20% SiO.sub.2, 4-50% TlO.sub.0.5, and 0-71% PbO, wherein PbO+T10.sub.0.5.gtoreq.25 %, TeO.sub.2 +SiO.sub.2 .gtoreq.25%, and TeO.sub.2 +SiO.sub.2 +TlO.sub.0.5 +PbO constitutes at least 65% of the total composition.

Abstract: A bonding glass for assembling a magnetic head by bonding a magnetic core to a non-magnetic ceramic slider. The magnetic core has a gap and an Fe-Al-Si film within the gap. The bonding glass includes SiO.sub.2 in the range of 6 to 11 wt %, B.sub.2 O.sub.3 in the range of 5 to 9 wt %, Al.sub.2 O.sub.3 in the range of 2 to 5 wt %, PbO in the range of 55 to 70 wt %, Bi.sub.2 O.sub.3 in the range of 5 to 15 wt %, TeO.sub.2 in the range of 1 to 10 wt % and CuO in the range of 0.5 to 2 wt %. A part of the PbO in PbO-SiO.sub.2 -B.sub.2 O.sub.3 -Al.sub.2 O.sub.3 glass is replaced with TeO.sub.2 and Bi.sub.2 O.sub.3 and, at the same time, CuO is added in order to prevent the formation of a heterophase. Glass color change under high temperature and high humidity is prevented.

Abstract: A resistor composition comprising a pyrochlore-related oxide a glass frit and, anorthite as a finely-divided filler. The resistor composition exhibits high tolerance in respect to firing temperatures. Thick film resistors obtained therefrom by firing on, for example, aluminum oxide substrates, have relatively uniform resistance values, even with inconsistent firing conditions, and have high stability of resistance following laser trimming.

Abstract: The present invention relates to a moisture resistant low melting point glass composition for a magnetic head and a magnetic head utilizing it. Said glass composition may be composed of 28-35% PbO, 38-50% SiO.sub.2, 3-10% R.sub.2 O, 3-8% TeO.sub.2, and 1-5% TiO.sub.2 in terms of mole ratio, or 30-40% PbO, 30-40% SiO.sub.2, 10-20% B.sub.2 O.sub.3, 8% or less TeO.sub.2 and 10% or less Bi.sub.2 O.sub.3, cr 30-40% PbO, 30-40% SiO.sub.2, 10-20% B.sub.2 O.sub.3, and 0-8% TeO.sub.2, or 30-40% PbO, 30-40% SiO.sub.2, 10-20% B.sub.2 O.sub.3, and 0-10% Bi.sub.2 O.sub.3.

Abstract: A process for producing a curved glass plate, which comprises coating a crystallizable ceramic color composition to a predetermined portion of a glass plate, followed by baking at a temperature of from 500.degree. to 620.degree. C. to fuse the ceramic color composition to the glass plate, then crystallizing the fused ceramic color composition at a temperature of from 600.degree. to 700.degree. C., followed by bend-shaping by a pressing apparatus in a furnace.

Abstract: This invention relates to glasses exhibiting very high optical non-linearity, very high Verdet constants, very high electro-optic constants, and excellent transmissions of infrared radiation. The glasses consist essentially, in cation percent, of:______________________________________ T10.sub.0.5 20-55 GeO.sub.2 0-17 BiO.sub.1.5 0-67 PbO 0-40 GaO.sub.1.5 13-30 T10.sub.0.5 + BiO.sub.1.5 + PbO 70-87 SiO.sub.2 0-5 TeO.sub.

Abstract: This invention is drawn to heavy metal oxide glasses exhibiting high nonlinear susceptibility and infrared transmission consisting essentially, in weight percent, of 42-48% PbO, 33-44% Bi.sub.2 O.sub.3, 10-15% Ga.sub.2 O.sub.3, and up to 15% total of at least one member of the group consisting of up to 5% SiO.sub.2 and/or GeO.sub.2 and up to 15% Tl.sub.2 O. This invention also comprehends the fabrication of light guiding fibers from those glasses.

Abstract: The invention is a process to manufacture a controlled-porosity ceramic material by synthesizing an aerogel produced by hypercritical drying of a high-porosity gel.Applications in the submarine acoustic field (active and passive sonars).

Abstract: This invention is drawn to heavy metal oxide glasses exhibiting high nonlinear susceptibility and infrared transmission consisting essentially, in weight percent, of 42-48% PbO, 33-44% Bi.sub.2 O.sub.3, 10-15% Ga.sub.2 O.sub.3, and up to 15% total of at least one member of the group consisting of up to 5% SiO.sub.2 and/or GeO.sub.2 and up to 15% Tl.sub.2 O. This invention also comprehends the fabrication of light guiding fibers from those glasses.