Abstract: This invention is directed to the production of glass articles transparent to visible radiation, but opaque to ultraviolet radiation, rendering them particularly suitable for protecting the wearer of such lenses from exposure to laser radiation in the ultraviolet regions of the electromagnetic spectrum. The method involves exposing silver halide-containing glass articles to flowing hydrogen in a heat chamber operating at 375.degree.-500.degree. C. for at least four hours to produce an integral reduced layer in at least one surface of the articles of sufficient depth to prevent the transmission of ultraviolet radiation through the articles.

Abstract: The borosilicate glass has a UV transmission of at least 80% at a UV wavelength of about 254 nm for a borosilicate glass sheet thickness of 2 mm, a linear coefficient of thermal expansion, .alpha..sub.20/300, of 3.2 to 3.4.times.10.sup.-6 K.sup.-1, a hydrolytic resistance of class 1 and a composition in % by weight based on oxide of______________________________________ glass formers <96%, SiO.sub.2 from 79.0 to 81.0%, B.sub.2 O.sub.3 from 12.5 to 13.0%, Al.sub.2 O.sub.3 from 2.0 to 4.0%, alkali metal oxides >2%, ______________________________________wherein said alkali metal oxides include from 2.0 to 3.5% said K.sub.2 O and from 1.0 to 2.0% said Li.sub.2 O, ______________________________________ alkaline earth metal <0.3%, oxides + ZnO reducing agent 0.025 to 2%, and non-oxidizing fining agent 0 to 3%. ______________________________________The weight ratio of K.sub.2 O to Li.sub.2 O is from 2:1 to 1:1 in the borosilicate glass.

Abstract: The present invention relates to writing and marking images on ceramic surfaces in a reversible fashion. The images are marked using a laser. The images are erased by heating the ceramic surfaces to a temperature of approximately 200.degree. C. or using a CO.sub.2 laser.

Abstract: A non-photochromic colored glass containing crystals of precipitated cuprous oxide in a matrix of glass, the matrix glass consisting essentially of, in cation percent, 35-75% SiO.sub.2, 15-45% B.sub.2 O.sub.3, 0-12% Al.sub.2 O.sub.3, the Al.sub.2 O.sub.3 being less than 10% when the SiO.sub.2 is over 55%, 0-5% ZrO.sub.2, 0-12% Li.sub.2 O, 0-20% Na.sub.2 O, 0-12% K.sub.2 O, the sum Li.sub.2 O+Na.sub.2 O+K.sub.2 O being 5-20%, 0-5% CaO+BaO+SrO, 0.4-1.75% Cu.sub.2 O, 0-2% As.sub.2 O.sub.3, 0-2% Sb.sub.2 O.sub.3, 0-1% SnO.sub.2, the sum As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 +SnO.sub.2 being 0.5-2%, characterized by 0.075.ltoreq.R-value .ltoreq.0.

Abstract: This invention is directed to the production of a silver halide-containing glass article essentially free from silver halide crystals exhibiting a bright yellow coloration which strongly attenuates the transmission of ultraviolet radiation and radiation having a wavelength up to about 450 nm, said article having an integral reduced surface layer thereon, the depth of that layer being sufficient to effectively prevent the transmission therethrough of ultraviolet radiation and radiation having a wavelength up to about 450 nm.

Abstract: This invention is directed primarily to a composition for a photochromic glass which is essentially colorless in the undarkened state consisting essentially, expressed in terms of weight percent, of______________________________________ SiO.sub.2 54-58 TiO.sub.2 0-2 PbO 0-0.8 B.sub.2 O.sub.3 18-22 ZrO.sub.2 2-4.5 Sb.sub.2 O.sub.3 0-0.2 Al.sub.2 O.sub.3 7-8 Ag 0.155-0.175 Er.sub.2 O.sub.3 0-0.5 Li.sub.2 O 3.75-4.5 Cl 0.3-0.4 Au 0-5 ppm Na.sub.2 O 0-1 Br 0.08-0.11 Pd 0.8-1.2 ppm K.sub.2 O 5.5-7.5 CuO 0.0065-0.01 ______________________________________wherein the mole ratio Li.sub.2 O:Na.sub.2 O.gtoreq.9:1, said glass at a thickness of 2 mm exhibiting a coloration in the fully darkened state corresponding to the chromaticity coordinates, in accordance with the 1931 C.I.E. trichromatic colorimetric system, falling within area IJKLI in the appended drawing.

Abstract: A surface-reduced photochromic glass containing silver halide crystals, having an original transmittance of 60-75%, a darkened transmittance of less than 30% at 25.degree. C., a faded transmittance equal to the darkened transmittance plus at least 25% and a value of at least 50%, a position in a color mixture diagram between 575 and 585 nm, the glass composition having a Na.sub.2 O content of at least 1% in its surface, or containing as additives 1-6 ppm Pd, or a combination of 2-10 ppm Au and up to 0.9% Er.sub.2 O.sub.3. The glass may be chemically strengthened and generally has a longer dominant wavelength when so treated.

Abstract: This invention is directed to photochromic glasses which darken to a brown coloration upon exposure to actinic radiation, which glasses have a refractive index of about 1.6, an Abbe number between 42-47, a density less than 2.82 g/cm.sup.3, and are preferably essentially free of TiO.sub.2. The glass compositions consist generally, in weight percent, of:______________________________________ SiO.sub.2 43-52 K.sub.2 O 2-9 Nb.sub.2 O.sub.5 6-16 B.sub.2 O.sub.3 12.5-18 MgO 0-5 Ag 0.100-0.175 Al.sub.2 O.sub.3 0-3 CaO 0-5 Cl 0.140-0.350 ZrO.sub.2 6-14 SrO 0-9 Br 0.093-0.195 Li.sub.2 O 1.5-3.5 BaO 0-9 CuO 0.008-0.030. Na.sub.

Abstract: A high-refractive index phototropic glass having a refractive index of 1.69 to more than 1.7, an Abbe coefficient of at least 35 and a density of at most 3.5 g/cm.sup.3, has a composition (in % by weight based on oxide) of: SiO.sub.2 15-33; B.sub.2 O.sub.3 12-22; .SIGMA. SiO.sub.2 +B.sub.2 O.sub.3 30-50; Li.sub.2 O 0.5-5.0; Na.sub.2 O 0-3; K.sub.2 O 0-11; .SIGMA. alkali oxides 4-12; BaO 0-23; SrO 0-23; .SIGMA. SrO+BaO 0-23; ZrO.sub.2 5-14; Nb.sub.2 O.sub.5 15-24; Ta.sub.2 O.sub.5 2-11. As the carrier of the phototropism, the glass also has 0.10 to 0.35 of Ag.sub.2 O; 0.15-0.65 of Cl; 0.15-0.45 of Br and 0.005-0.030 of CuO. The glass can also be doped with 1-3 ppm of gold or one or more platinum metals, especially palladium.

Abstract: A non-photochromic R.sub.2 O-B.sub.2 O.sub.3 -SiO.sub.2 glass containing a cuprous or cuprous-cadmium halide crystal phase, having a sharp spectral cutoff at about 400 nm, the glass composition consisting essentially of, in cation percent, 35-73% SiO.sub.2, 15-45% B.sub.2 O.sub.3, 0-12% Al.sub.2 O.sub.3, the Al.sub.2 O.sub.3 being less than 10% when the SiO.sub.2 is over 55%, 0-12% Li.sub.2 O, 0-20% Na.sub.2 O, 0-12% K.sub.2 O, the Li.sub.2 O+Na.sub.2 O+K.sub.2 O being 4.75-20%, 0-5% CaO+BaO+SrO, 0.125-1.0% Cu.sub.2 O, 0-1% CdO, 0-5% ZrO.sub.2, 0-0.75% SnO.sub.2, 0-1% As.sub.2 O.sub.3 and/or Sb.sub.2 O.sub.3, the glass containing 0-1.75%. Cl, 0-1.0% Br, 0.25-2.0% Cl+Br and 0-2% F by weight, and having an R-value, calculated in mole percent of 0.15-0.45, the R-value not exceeding 0.30, except as the glass composition meets at least one condition selected from the group: up to 12 cation % Li.sub.2 O, less than 10 cation % Al.sub.2 O.sub.3, at least 0.3 cation % Cu.sub.2 O and 0.50-2.0% Cl+Br.

Abstract: A transparent photochromic glass displaying a pink hue in the darkened state which, in bodies of 2 mm cross section, will exhibit the following optical properties:(a) a clear (undarkened) luminous transmittance greater than 82%;(b) a darkened luminous transmittance after 15 minutes' exposure to actinic radiation at 25.degree. C. between about 20-32%;(c) a darkened luminous transmittance after 15 minutes' exposure to actinic radiation at 40.degree. C. between about 35-55%;(d) a rate of fading such that the luminous transmittance after 5 minutes' removal from actinic radiation at 25.degree. C. will be at least 30 percentage units higher and will exhibit a luminous transmittance greater than 50%;(e) a x trichromatic coordinate between 0.3500 and 0.3700; and(f) a y trichromatic coordinate between 0.3250 and 0.3450;said glass consisting essentially, expressed in terms of weight percent on the oxide basis, of______________________________________ SiO.sub.2 52-58 ZrO.sub.2 1.5-2.8 K.sub.2 O 4-8 B.sub.2 O.sub.

Abstract: Thermally induced color is developed in a glass article containing a silver halide crystal phase by including in the glass batch a thermal reducing agent, retaining the thermal reducing agent in its lower valence state while meltinq the batch and forming the glass article and subsequently heat treating the article to partially reduce the silver halide crystal phase.

Abstract: A silver halide photochromic glass hasa. a clear luminous transmittance of about 90%,b. A darkened luminous transmittance at 20.degree. C. below about 25%.c. A fading rate at 20.degree. C. such that, after a five minute fading interval, the glass exhibits a percent faded luminous transmittance that is no more than the darkened luminous transmittance percentage plus 15. The glass has an R.sub.2 O--Al.sub.2 O.sub.3 --B.sub.2 O.sub.3 --SiO.sub.2 base composition, contains as additives, in percent by weight, 0.1-0.3% Ag, 0.25-1.0% Cl, 0-0.2% Br, 0.25-1.0% Cl+Br, the ratio of Ag:(Cl+Br) being 0.15-0.65, 0.003-0.015% CuO and 0.1-1.0% PbO and the total R.sub.2 O content is 8-13.5%, wherein R.sub.2 O consists of Li.sub.2 O+Na.sub.2 O +K.sub.2 O.

Abstract: This invention is directed to a glass containing elongated silver halide crystals selected from the group consisting of AgCl, AgBr, AgI, and mixtures thereof which is capable of polarizing radiation in the visible portion of the radiation spectrum and which does not exhibit photochromism when exposed to radiation in the ultraviolet/visible portions of the radiation spectrum, wherein the composition of the glass is essentially free of copper and includes an amount of CeO.sub.2 effective to retain the silver in the glass composition in the oxidized state.

Abstract: A composition for a photochromic glass consisting essentially of, in approximate calculated weight percent, about:______________________________________ SiO.sub.2 54-58% Ag 0.18-0.33% B.sub.2 O.sub.3 18-22% Cl 0.25-0.50% Al.sub.2 O.sub.3 7-8% Br 0.04-0.12% Li.sub.2 O 3.75-4.5% CuO 0.007-0.012% Na.sub.2 O 0-1% PbO 0-0.08% K.sub.2 O 5.5-7.5% Sb.sub.2 O.sub.3 0-0.20% TiO.sub.2 0-2% Pd 1-6 ppm ZrO.sub.2 2-4.5% ______________________________________plus 0-1.0% Er.sub.2 O.sub.3 and/or 0-10 ppm Au, the mole ratio of Li.sub.2 O:Na.sub.2 O being equal to or greater than 9:1 and the glass having a coloration in the fully darkened state corresponding to chromaticity coordinates, in accordance with the 1931 C.I.E. trichromatic colorimetric system, that fall within the trapezoid ABCDA in the drawing for a 1.1 mm glass thickness, and within the trapezoid EFGHE for a 2 mm glass thickness.

Abstract: A highly refractive, low-density phototropic glass in which the carriers of phototropy are precipitates containing silver, halogens and copper oxide, and which has a density equal to or less than 3.0 g/cm.sup.3, a refractive index equal to or greater than 1.60 and an Abbe number equal to or greater than 40, consisting essentially of, in % by weight on an oxide basis:______________________________________ SiO.sub.2 35-50 B.sub.2 O.sub.3 13.5-21 .SIGMA.SiO.sub.2 and B.sub.2 O.sub.3 50-70 Li.sub.2 O 0.0-2.5 Na.sub.2 O 0.0-4.0 K.sub.2 O 0.0-10.0 .SIGMA.Alkali metal oxides 4-14 BaO.sub.2 5.0-10.5 TiO.sub.2 3.5-6.5 ZrO.sub.2 4.5-9.5 Nb.sub.2 O.sub.3 5.0-11.5, ______________________________________the total of the foregoing oxides being 100% by weight, and in addition to the basic glass composition, carriers of phototropy consisting essentially of, in % by weight: ______________________________________ Ag.sub.2 O 0.05-0.25 Br 0.07-0.25 Cl 0.06-0.35 .SIGMA.Br and Cl .ltoreq.0.5 CuO 0.003-0.015.

Abstract: A photosensitive borosilicate glass which consists essentially in calculated weight percent on an oxide basis of 20-80% SiO.sub.2, 8-40% B.sub.2 O.sub.3, 0-6% Li.sub.2, 0-28% Na.sub.2, 0-25% K.sub.2 O, the total Na.sub.2 O+K.sub.2 O being 10-28%, 0-18% Al.sub.2 O.sub.3 and minor amounts of photosensitizing agents silver, cerium oxide, antimony oxide and bromine and/or chlorine, the cation ratio of R.sub.2 O--Al.sub.2 O.sub.3 to B.sub.2 O.sub.3 being at least 0.6.

Abstract: This invention relates to the production of glasses exhibiting a refractive index between about 1.66-1.81, a softening point between about 625.degree.-675.degree. C., a strain point between about 455.degree.-490.degree. C., a linear coefficeint of thermal expansion (25.degree.-300.degree. C.) between about 53-65.times.10.sup.-7 /.degree.C., and good chemical durability which consist essentially, in weight percent, of:______________________________________ SiO.sub.2 24-42 Li.sub.2 O 0.2 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-3.5 Al.sub.2 O.sub.3 3-7.5 Na.sub.2 O 0-2 ZrO.sub.2 0-2.5 B.sub.2 O.sub.3 2-7.5 K.sub.2 O 0-3 TiO.sub.2 0-8 PbO 35-57 La.sub.2 O.sub.3 0-8 La.sub.2 O.sub.3 + ZrO.sub.2 4-12.sub.

Abstract: A highly refractive, low-density phototropic glass in which the carriers of phototropy are precipitates containing silver, halogens and copper oxide, and which has a density equal to or less than 3.0 g/cm.sup.3, a refractive index equal to or greater than 1.60 and an Abbe number equal to or greater than 40, consisting essentially of, in % by weight on an oxide basis:SiO.sub.2 : 35-50B.sub.2 O.sub.3 : 13.5-21.SIGMA.SiO.sub.2 and B.sub.2 O.sub.3 : 50-70Li.sub.2 O: 0.0-2.5Na.sub.2 O: 0.0-4.0K.sub.2 O: 0.0-10.0.SIGMA.Alkali metal oxides: 4-14BaO: 5.0-10.5TiO.sub.2 : 3.5-6.5ZrO.sub.2 : 4.5-9.5Nb.sub.2 O.sub.3 : 5.0-11.5,and in addition to the basic glass composition, carriers of phototropy consisting essentially of, in % by weight:Ag.sub.2 O; 0.05-0.25Br: 0.07-0.25Cl: 0.06-0.35.SIGMA.Br and Cl: .ltoreq.0.5CuO: 0.003-0.015.

Abstract: The invention relates to high energy beam-sensitive glass articles exhibiting insensitivity and/or inertness to actinic radiation, glass articles which are darkened and/or colored within a thin surface layer of about 0.1-3 .mu.m upon exposure to a high energy beam, electron beam, and ion beams in particular, without a subsequent development step, and which need no fixing to stabilize the colored image, since both the recorded image and the glass article are insensitive to radiation in the spectral range of uv and longer wavelengths. The instant invention is concerned with Ag.sup.+ ion-exchanged glass articles having base glass within alkali metal silicate composition fields containing at least one of the oxides of transition metals which have one to four d-electrons in an atomic state. The base glass composition can be varied widely, spontaneous reduction as well as photo-reduction of Ag.sup.+ ions are inhibited and/or eliminated due to the presence of said transition metal oxides in the glass article.

Abstract: A crystallized glass article with a colored surface pattern, which comprises a crystallized glass substrate having a surface and small glass masses having a color different from the substrate and dispersed and fusion-bonded in the surface to form the colored surface pattern. The crystallized glass article is produced by depositing and dispersing small glass masses with a color on a surface of a substrate of a crystallizable glass with a different color which can precipitate crystals therein with softening and deforming by heat-treating at a heat treating temperature higher than the softening point of the crystallizable glass, then heating the substrate together with the small glass masses at the heat treating temperature.

Abstract: Glasses containing chromophores are partially struck to produce no coloring or only light coloring due to the chromophore. The glasses are colored as desired by contents of colorant ions.

Abstract: A process for preparing a surface-darkened glass is disclosed. In the first step of this process, a specified silicate glass which contains a minor amount of antimony trioxide is provided. Thereafter, this glass is heated to a temperature of from about 350 to about 1,000 degrees Celsius while being contacted with hydrogen-containing gas. The presence of the antimony trioxide in the glass facilitates the darkening of its surface.

Abstract: This invention is directed to the preparation of silver halide-containing photochromic glasses exhibiting refractive indices between 1.585-1.610, Abbe numbers higher than 41, and densities less than 2.80 g/cm.sup.3 generally consisting essentially, in weight percent, of:______________________________________ SiO.sub.2 43-52 SrO 0.8-9 B.sub.2 O.sub.3 12.5-18 BaO 1-9 Al.sub.2 O.sub.3 0-3 K.sub.2 O 2-9 ZrO.sub.2 3-8 TiO.sub.2 2-8 Li.sub.2 O 1.5-3.5 Ag 0.100-0.175 Na.sub.2 O 0.3-3 Cl 0.140-0.350 Nb.sub.2 O.sub.5 4-9 Br 0.093-0.180 MgO 0-5 CuO 0.0080-0.

Abstract: This invention is directed to photosensitively opacifiable glasses consisting essentially, in weight percent, of about 14-18% Na.sub.2 O, 0-6% Zno, 6-12% Al.sub.2 O.sub.3, 0-5% B.sub.2 O.sub.3, 0-0.2% Sb.sub.2 O.sub.3, 0-0.1% SnO, 65-72% SiO.sub.2, and 0.007-0.04% Ag, 0.008-0.05% CeO.sub.2, 0.7-1.25% Br, and 1.5-2.5% F as analyzed in the glass, the sum of those components constituting at least 90% of the total composition, which, through an exposure to ultraviolet radiation, followed by a three-step heat treatment, and then a re-exposure to ultraviolet radiation at an elevated temperature, can be converted into a colored opal glass.

Abstract: This invention relates to the production of an essentially colorless alkali meal oxide-Al.sub.2 O.sub.3 and/or B.sub.2 O.sub.3 -SiO.sub.2, wherein at least a portion thereof contains silver ions resulting from an ion exchange reaction wherein Ag.sup.+ ions from an external source are exchanged with alkali metal ions in the glass. The amount of exchange can be varied across a portion of the glass to impart a gradient in refractive index thereto. Such technology is especially suited to the optical engineering field, particularly the making of high performance fiber-optic components.

Abstract: This invention is directed to a method for making tinted photochromic glass articles having an integral reduced surface layer exhibiting color, the glass utilizing silver halide crystals as the photochromic agent. The method generally comprises heat treating the glass article in a heating chamber in an atmosphere of flowing hydrogen at temperatures below 500.degree. C.

Abstract: This invention relates to photochromic glasses exhibiting refractive indices greater than 1.59, densities no higher than 3.1 g/cm.sup.3, Abbe numbers of at least 40, weight losses no greater than 0.01 mg/cm.sup.2 in the A.O. test, and which, when exposed to actinic radiation at room temperatures, darken to transmittances below 40% and fade at least 15 percentage points of transmittance after five minutes' removal from the actinic radiation.

Abstract: Photosensitively opacifiable glasses requiring very short exposures to ultraviolet radiation to effect the development of opacity are processed by heating to nucleate Ag followed by cooling to nucleate NaF on the Ag followed by heating to grow the NaF. The glasses contain, expressed in terms of weight percent on the oxide basis, about 14-18% Na.sub.2 O, 0-6% ZnO, 6-12% Al.sub.2 O.sub.3, 0-5% B.sub.2 O.sub.3, 65-72% SiO.sub.2, and 0-0.2% Sb.sub.2 O.sub.3, and 0.007-0.04% Ag, 0.008-0.05% CeO.sub.2, 0.7-1.25% Br, and 1.5-2.5% F as analyzed in the glass, the sum of those components are at least 90% of the total composition.

Abstract: A process for preparing a surface-darkened glass is disclosed. In the first step of the process, a specified alkali alumino-borosilicate glass which contains a minor amount of antimony trioxide is provided. Thereafter, this glass is heated to a temperature of from about 350 to about 1,000 degrees Celsius while being contacted with hydrogen-containing gas. The presence of the antimony trioxide in the glass facilitates the darkening of its surface.

Abstract: This invention is directed to the preparation of glass articles exhibiting a relatively broad band of high contrast polarizing properties in the infrared region of the radiation spectrum from glasses containing silver halide particles selected from the group consisting of AgCl, AgBr, and AgI. The inventive method comprises the following five general steps:(a) melting a batch for a glass containing silver and at least one halide selected from the group consisting of chloride, bromide, and iodide;(b) cooling and shaping said melt into a glass article of a desired configuration;(c) subjecting said glass article to a temperature at least above the strain point, but not in excess of 75.degree. C. above the softening point of the glass, for a sufficient length of time to cause the generation of silver halide particles therein selected from the group consisting of AgCl, AgBr, and AgI, said particles ranging in size between about 200-5000 .ANG.

Abstract: The invention relates to high energy beam-sensitive glass articles exhibiting insensitivity and/or inertness to artinic radiation, i.e., glass articles which are darkened and/or colored within a thin surface layer of, e.g., about 0.1-3 .mu.m upon exposure to high energy beams, electron beams, and ion beams in particular, without a subsequent development step, and which need no fixing to stabilize the colored image, since both the recorded image and the glass article are sensitive to radiation in the spectral range of UV, and longer, wavelengths. More particularly, the instant invention is concerned with Ag+ ion-exchanged glass articles having base glass within alkali metal silicate composition fields containing at least one of the oxides of transition metals which have one to four d-electrons in an atomic state.

Abstract: The present invention is related to transparent, fast darkening and fading photochromic glasses.The glasses contain SiO.sub.2, B.sub.2 O.sub.3, Al.sub.2 O.sub.3, ZrO.sub.2, Li.sub.2 O, Na.sub.2 O, K.sub.2 O, MgO, CaO, SrO, BaO, ZnO, La.sub.2 O.sub.3, Nb.sub.2 O.sub.5, TiO.sub.2 as base glass components, Ag, Br, Cl, CuO as photochromic elements, with, optionally, Sb.sub.2 O.sub.3, As.sub.2 O.sub.3, and SnO.sub.2 as colorants to impart a brown color at darkening.The glasses have a refractive index greater than 1.585, an Abbe number greater than 42, and a density lower than about 2.80 g/cm.sup.3.

Abstract: A metod for making a photochromic glass article exhibiting a surface color pattern wherein a silver halide-containing photochromic glass article is treated by exposing at least a portion of the surface thereof to a patterned heat source for a time sufficient to raise the temperature of at least a part of the exposed portion above about 450.degree. C., is described. The glass may be exposed to the patterned heat source either before or after thermal reduction coloring. Patterned heating to a temperature in the transformation range of the glass is used where a post-patterning thermal reduction coloration step is to be used, in order to render the glass resistant to reduction coloration in the patterned area.

Abstract: An optically activated bleaching process effective to permanently modify the color of surface-colored silver halide-containing photochromic glasses produced by thermal reduction treatments is described, wherein the glass is coincidentally exposed, for an effective time interval, to (i) a source of high energy light and (ii) a heat source. The process reduces the relatively strong absorption peaks characteristic of the initially colored glass, resulting in a permanent bleached appearance.

Abstract: A method for modifying surface coloration in silver halide-containing photochromic glasses developed by thermal reduction treatments is described, which method comprises subjecting the glass, prior to the coloring thermal reduction treatment, to a silver ion exchange treatment during which silver ions are introduced into at least a portion of the surface of the glass article. Subsequent thermal reduction of the silver-containing surface portion of the glass provides novel colors and/or color patterns therein.

Abstract: This invention is directed to a method for heat treating a sheet of a potentially photochromic glass to cause the growth of silver halide crystals therein which impart photochromic properties thereto, wherein the heat treated sheet will be essentially free from thermal deformation and surface defects, and the photochromic properties exhibited therein will be essentially uniform across the area of the sheet. The method involves first placing a sheet of potentially photochromic glass on top of a sheet of carrier glass that exhibits a softening point at least 50.degree. C. higher than the temperature at which the potentially photochromic glass will be heat treated, and thereafter subjecting the stacked sheets to the heat treatment temperature desired for growing silver halide crystals in the glass.

Abstract: A television face plate resistant to browning is formed by melting and refining molten glass which contains cerium oxide as an anti-browning agent, the process being carried out in the presence of a sulphur containing compound such that the cerium oxide is converted substantially into the cerous state during melting and refining thereby increasing resistance to browning.

Abstract: A method of laser marking ceramic materials, glazes, glass ceramics and glasses that contain at least one radiation-sensitive additive, utilizing a laser beam as radiation energy source which is either applied to, or focused on, the surface of the material to be marked in accordance with the form of the graphic symbols to be reproduced, such that a change in color is induced at the irradiated areas, wherein the wavelength of said laser beam used as energy source is in the near UV and/or visible range and/or infra-red range, and the radiation-sensitive additive is an inorganic pigment.

Abstract: This invention relates to the production of lightly tinted, photochromic glasses having base compositions consisting essentially, in weight percent, of______________________________________ SiO.sub.2 46-60 SrO 0-6 B.sub.2 O.sub.3 16-28 BaO 0-6 Al.sub.2 O.sub.3 4-11 P.sub.2 O.sub.5 0-5 ZrO.sub.2 2-6 TiO.sub.2 0-3 Li.sub.2 O 1.5-5 Ag 0.08-0.18 Na.sub.2 O 0-6 Cl 0.06-0.26 K.sub.2 O 2.5-9 Br 0.08-0.18 MgO 0-3.5 CuO 0.0001-0.0020 CaO 0-6 ______________________________________Glass color can be adjusted by introducing in excess of the above base composition, at least one of the following colorants in the indicated proportions of ______________________________________ Pd 0.00003-0.00015 Er.sub.2 O.sub.3 0.2-1.3 SnO.sub.2 0.05-0.3 Nd.sub.2 O.sub.3 0-0.7 Fe.sub.2 O.sub.3 0.05-0.15 Co.sub.3 O.sub.4 0-0.0080 NiO 0.005-0.

Abstract: This invention is directed to transparent photochromic glasses that can darken to a comfort range, i.e., between about 35-60%, or to a dark range, i.e., below 35%, depending upon glass composition, and will exhibit a faded transmittance after five minutes' removal from actinic radiation higher than 70%. The base compositions of the glasses consist essentially, in weight percent, of about______________________________________ SiO.sub.2 46-60 MgO 0-3.5 B.sub.2 O.sub.3 16-28 CaO 0-6 Al.sub.2 O.sub.3 4-11 SrO 0-6 ZrO.sub.2 2-6 BaO 0-6 Al.sub.2 O.sub.3 + ZrO.sub.2 6-13 MgO + CaO + SrO + BaO 0-7 Li.sub.2 O 2-5 P.sub.2 O.sub.5 0-5 Na.sub.2 O 0-4 TiO.sub.2 0-3 K.sub.2 O 2.5-9 ______________________________________For a comfort glass the photochromic elements consist essentially, as analyzed, of ______________________________________ Ag 0.13-0.18 Br 0.08-0.14 Cl 0.16-0.34 CuO 0.001-0.

Abstract: A ceramic substrate supports a thin or thick film electronic circuit hermetically enclosed by a vitreous glass covering sealed to the ceramic substrate by a heat fused vitreous sealing glass. The vitreous sealing glass is screened onto the vitreous glass covering in a composition comprising a binder material and a liquifier. The electronic circuit is trimmed by a laser beam directed through the vitreous glass covering as one of the final process steps after completion of those process steps which tend to affect the resistivity of the resistive element; process steps such as high temperature baking and soldering of component parts.

Abstract: This invention is directed to a method for modifying the coloration produced in a silver halide-containing photochromic glass when heat treating the glass at a temperature not exceeding 450.degree. C. under reducing conditions. The method comprises subjecting such a glass having a base composition which contains at least 1% by weight Li.sub.2 O, at least 2% by weight Na.sub.2 O, and at least 6% by weight Li.sub.2 O+Na.sub.2 O+K.sub.2 O to an ion exchange reaction, wherein lithium ions, and potassium ions, when the latter are present in the composition, in the glass surface are exchanged with sodium ions from an external source, prior to the reduction heat treatment.

Abstract: The invention relates to a photosensitive and heat-sensitive glass which is composed of 25-70 mol % of Al.sub.2 O.sub.3 and/or Ga.sub.2 O.sub.3, 30-75 mol % of at least one of CaO, BaO, SrO and MgO and 0-40 mol % of an auxiliary component which is at least one of SiO.sub.2, GeO.sub.2, B.sub.2 O.sub.3 and P.sub.2 O.sub.5. The glass is produced by melting a batch mixture of powdery raw materials. By exposure to UV rays the glass colors in yellowish brown, and the color does not fade by termination of the exposure. Bleaching of the colored glass is accomplished by heating for a short time at about 150.degree.-300.degree. C. Coloration and bleaching can be repeated without deterioration. The same glass turns into an opaline foam glass, which presents a very attractive appearance, by heat treatment at a temperature above the softening temperature. This change is irreversible. The foams created in the glass matrix are usually tens of microns in diameter.

Abstract: A phototropic glass with the optical characteristics of n.sub.d greater than to or equal to 1.59 and v.sub.d greater than or equal to 44, and with a density less than or equal to 3.0 g/cm.sup.-3 is provided having a composition comprising:______________________________________ SiO.sub.2 42-56 B.sub.2 O.sub.3 11-18 Al.sub.2 O.sub.3 0-5 sum of SiO.sub.2, B.sub.2 O.sub.3, and Al.sub.2 O.sub.3 55-75 Li.sub.2 O 3-9 Na.sub.2 O 0-7.98 K.sub.2 O 0-8.22 sum of alkaki metal oxides 7-15 MgO 3-12 CaO 0-3 SrO 0-3 BaO 0-6 ZnO 0-2 sum of alkali earth metal 3-12 oxides amd ZnO TiO.sub.2 3.06-6.74 ZrO.sub.2 2-11 Nb.sub.2 O.sub.5 2.28-8 La.sub.2 O.sub.3 0-3 Er.sub.2 O.sub.

Abstract: The invention relates to high energy beam-sensitive glass articles exhibiting insensitivity and/or inertness to actinic radiation, i.e., glass articles which are darkened and/or colored within a thin surface layer of, e.g., about 0.1-3 .mu.m upon exposure to a high energy beam, electron beam, and ion beams in particular, without a subsequent development step, and which need no fixing to stabilize the colored image, since both the recorded image and the glass article are sensitive to radiation in the spectral range of uv and longer wavelengths. More particularly, the instant invention is concerned with Ag.sup.+ ion-exchanged glass articles having base glass within alkali metal silicate composition fields containing at least one of the oxides of transition metals which have one to four d-electrons in an atomic state. Whereas the base glass composition can be varied widely, spontaneous reduction as well as photo-reduction of Ag.sup.

Abstract: A step gradient photochromic glass body is produced by illuminating a selected region of a photochromic glass during isothermal heat treatment with light of a specified energy and intensity while shielding the rest of the glass. The regions of glass exposed to this light during heat treatment are arrested in the development of their photochromic properties, while those regions which are simultaneously shielded from light develop their photochromic properties normally. The light gradient across the glass body during heat treatment is effective to provide a similar gradient in photochromic properties thereacross.

Abstract: Photochromic glass compositions for thin refractive-index-corrected lens elements consisting essentially of about:______________________________________ SiO.sub.2 54-58% B.sub.2 O.sub.3 18-22% Al.sub.2 O.sub.3 7-8% Li.sub.2 O 3.75-4.5% Na.sub.2 O 0-1% K.sub.2 O 5.5-7.5% TiO.sub.2 0-2% ZrO.sub.2 2-4.5% Ag 0.20-0.33% Cl 0.30-0.50% Br 0.04-0.12% CuO 0.007-0.012% PbO 0-0.08% Sb.sub.2 O.sub.3 0-0.20% ______________________________________having a Li.sub.2 O:Na.sub.2 O molar ratio of at least 9:1 and exhibiting good darkening, fast fading, good chemical strengthenability and neutral dark-state coloration at thicknesses on the order of 1 mm, are described.

Abstract: A method for preparing reversible-photochromic magnesium oxide (MgO) crystals. Single crystals of MgO doped with both lithium (Li) and nickel (Ni) are grown by a conventional arc fusion method. The as-grown crystals are characterized by an amber coloration. The crystals lose the amber coloration and become photochromic when they are thermochemically reduced by heating at temperatures greater than 1000.degree. K. in a hydrogen atmosphere. Alternate irradiation with UV and visible light result in rejuvenation and bleaching of the amber coloration, respectively.

Abstract: A ceramic substrate supports a thin or thick film electronic circuit hermetically enclosed by a vitreous glass covering sealed to the ceramic substrate by a heat fused vitreous sealing glass. The vitreous sealing glass is screened onto the vitreous glass covering in a composition comprising a binder material and a liquifier. The electronic circuit is trimmed by a laser beam directed through the vitreous glass covering as one of the final process steps after completion of those process steps which tend to affect the resistivity of the resistive element; process steps such as high temperature baking and soldering of component parts.