Abstract: This invention is directed to the preparation of haze-free photochromic glasses which darken to a comfort range, i.e., a luminous transmittance of about 40-60%, which exhibit very rapid fading, and which demonstrate excellent temperature dependence. The glasses consist essentially, in weight percent with the levels of Ag, Cu.sub.2 0, C1, and Br representing values as analyzed in the glass, of:______________________________________ Li.sub.2 O 0-2.5 P.sub.2 O.sub.5 0-25 Na.sub.2 O 0-9 SiO.sub.2 20-65 K.sub.2 O 0-17 Ag 0.115-0.145 Cs.sub.2 O 0-6 Br 0.11-0.155 Li.sub.2 O + Na.sub.2 O + K.sub.2 O + Cs.sub.2 O 8-20 B.sub.2 O.sub.3 14-23 Cu.sub.2 O 0.007-0.011 Al.sub.2 O.sub.3 5-25 Cl 0.1-0.15 ______________________________________and wherein the molar ratio alkali metal oxide: B.sub.2 0.sub.3 ranges between about 0.55-0.85, the weight ratio Ag:(C1+Br) ranges between about 0.65-0.95, and the sum of Ag+Br is at least 0.26%, when the Br content is 0.11%, and at least 0.25% when the Ag content is 0.115%.

Abstract: There is disclosed a method of producing a photochromic glass having a reduced transmittance for ultraviolet radiation while having substantially unimpaired photochromic properties. The method comprises providing a combination of 0.1-1.0% CeO.sub.2 and 0.1-1.5% Sb.sub.2 O.sub.3 and/or As.sub.2 O.sub.3 as part of the glass composition. In an embodiment utilizing minimal silver content, the glass article in thicknesses of 1.3 to 2.0 mm. can be chemically strengthened to surpass the impact specification imposed by the Federal Food and Drug Administration for eyewear, will transmit less than 0.2% of radiation having wavelengths between 290-315 nm, and will demonstrate a darkened luminous transmittance at 20.degree.-25.degree. C. below 35% and a fading rate such that after five minutes the luminous transmittance will be at least 1.75 times that of the darkened transmittance. These glasses consist essentially of:______________________________________ SiO.sub.2 55-61 Ag >0.1-<0.2 B.sub.2 O.sub.3 18-21 Cl 0.

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: Colored photochromic ophthalmic lenses are produced by combining a photochromic cap element having an integrally colored back surface with an ophthalmic crown base element having a prescription-ground back surface, the cap back and base element front surfaces having been finished to a matching standard base curvature, thus providing a cemented assembly exhibiting a selected combination of prescribed vision-correcting and light filtering properties.

Abstract: A method is set forth for making polarizing glasses having high dichroic ratios by drawing relatively small silver-containing particles under relatively high stress and elongating such particles during the drawing process without rupturing the glass draw by coating the polarizing glass with a substantially low viscosity skin glass.

Abstract: A phototropic glass with an optical position n.sub.d .ltoreq.1.59 and v.sub.d .gtoreq.40 and with a density of .ltoreq.3.2 g/cm.sup.3 is described for the first time. Its composition lies within the system ofSiO.sub.2 --R.sub.2 O.sub.3 --R.sub.2 O--RO--RO.sub.x --R.sub.2 O.sub.5,wherein R.sub.2 O.sub.3 is Al.sub.2 O.sub.3, B.sub.2 O.sub.3 and rare earth oxides; R.sub.2 O is alkali metal oxides; RO is alkaline earth metal oxides, ZnO, SnO, or PbO; RO.sub.x is GeO.sub.2, ZrO.sub.2, TiO.sub.2, or WO.sub.3 ; and R.sub.2 O.sub.5 is Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, or P.sub.2 O.sub.5.

Abstract: A new phototropic glass in which the phototropic properties arise from precipitations of silver halide and which in the unirradiated condition is slightly tinted or completely colorless while showing a brown color in the light-exposed condition, comprises, in known phototropic glass compositions, an additional content of at least 0.001 wt % of TeO.sub.2 and/or Yb.sub.2 O.sub.3.

Abstract: The instant invention is directed to the preparation of glass articles exhibiting excellent polarization in the infrared portion of the spectrum from glasses characterized as containing silver halide particles therein selected from the group of AgCl, AgBr, AgI. The inventive method comprises four general steps:(a) a batch for a glass containing silver and at least one halide selected from the group of chloride, bromide, and iodide is melted and the melt shaped into a glass body of a desired geometry;(b) the glass body is subjected to a heat treatment at least above the strain point but not in excess of 50.degree. C. above the softening point of the glass for a period of time adequate to cause the generation of AgCl and/or AgBr and/or AgI particles therein, said particles ranging in size between 200-5000 .ANG.;(c) the glass body is elongated under stress at temperatures above the annealing point, but below that where said glass exhibits a viscosity of about 10.sup.

Abstract: The present invention is directed to the preparation of photochromic glasses exhibiting a darkened luminous transmittance at 40.degree. C. below 35% and a five-minute fading rate at 40.degree. C. of at least 40 units of transmittance and a darkened transmittance at 25.degree. C. below 25% and a five-minute fading rate at 25.degree. C. of at least 35 units of transmittance. The glasses consist essentially, by weight, of:______________________________________ SiO.sub.2 56-60 Al.sub.2 O.sub.3 6-9 B.sub.2 O.sub.3 18-21 Li.sub.2 O >2.5-3.5 Na.sub.2 O 0.5-2.5 K.sub.2 O 5-7 ZrO.sub.2 3.75-5 PbO 0.1-0.15 Ag >0.15-0.25 Cl 0.2-0.35 Br 0.075-0.15 CuO 0.004-0.02 CeO.sub.2 0-0.5 ______________________________________wherein the levels of Ag, Br, Cl, and CuO represent values as analyzed in the glass.

Abstract: Mercury thallium fluorophosphate glasses are disclosed that have very low transition temperatures, very high refractive indices and dielectric constants, and are resistant to moisture attack. The glasses are free of alkali metals and substitute thallium chloride in the glass batch as a modifier. The melted glass is largely oxide in nature, but the halogens appear to facilitate melting of these soft glasses.

Abstract: There is disclosed a composite photochromic glass article composed of a glass core and a thin surface layer substantially encasing that core, the core preferably containing a copper-cadmium halide photochromic crystal system and the substantially encasing glass layer preferably containing a copper-cadmium-silver halide photochromic crystal system. The article may be made by fusion laminating two separately formed glasses, or by introducing silver into a surface layer on a glass article by ion exchange.

Abstract: This invention is directed to the production of transparent photochromic glasses containing silver halide crystals sensitized with copper having base compositions within the alkali metal aluminoborosilicate system wherein at least 0.025% As.sub.2 O.sub.3 and/or Sb.sub.2 O.sub.3 is present in the composition to insure that more than 50% of the copper is present in the Cu.sup.+ state. Where an oxidizing agent is added to the composition, the amount of As.sub.2 O.sub.3 and/or Sb.sub.2 O.sub.3 will be increased to reduce that agent plus insure that more than 50% of the copper is present in the Cu.sup.+ state.

Abstract: A tin-phosphorous oxyfluoride glass in the Sn--P--O--F composition field is used as a supporting matrix for light-responsive polycyclic aromatic hydrocarbons, such as triplet state or lasing dyes. Dye compatibility with the glass is good, as evidenced by the fact that glasses containing the dyes exhibit luminescence characteristic of the dissolved dye in a rigid solvent.

Abstract: The present invention is concerned with the production of photochromic glass compositions consisting essentially, expressed in terms of weight percent on the oxide basis, as calculated from the batch, of______________________________________ SiO.sub.2 52-59 B.sub.2 O.sub.3 18-23 Al.sub.2 O.sub.3 6-8 Li.sub.2 O 1-2.5 Na.sub.2 O 1-3 K.sub.2 O 8-13 ZrO.sub.2 2-6 TiO.sub.2 0-3 ______________________________________and containing, as analyzed in weight percent, of ______________________________________ Ag 0.17-0.22 CuO 0.012-0.019 Cl 0.29-0.35 Br 0.06-0.12 PbO 0.1-0.15 ______________________________________exhibiting, in 0.4 mm cross section, a clear luminous transmittance in excess of 90%, a darkened luminous transmittance below about 45% at a temperature of 25.degree. C., a darkened luminous transmittance below about 57% at a temperature of 40.degree. C., and a half fading time at both temperatures of about five minutes.

Abstract: The instant invention is directed to the production of photochromic glasses having compositions consisting essentially, as analyzed in weight percent on the oxide basis, ofSiO.sub.2 --55-60Al.sub.2 O.sub.3 --9-10B.sub.2 O.sub.3 --19-20.5Li.sub.2 O--2-2.5Na.sub.2 O--2-3K.sub.2 O--6-7PbO--0.1-0.25Ag--0.1-0.15Cl--0.3-0.5Br--0.05-0.15CuO--0.0065-0.01The glasses are capable of being drawn into sheet and articles cut from the sheet simultaneously shaped and photochromic properties developed therein. The glasses display a clear luminous transmittance in excess of 90% when free from tint, a darkened luminous transmittance at 20.degree. C. below 25% when free from tint, and a fading rate at 20.degree. C. such that the glass demonstrates a faded luminous transmittance at least twice that of the darkened transmittance after a five-minute fading interval.

Abstract: A process for producing a photochromic glass which will exhibit a brown coloration in its darkened state without a degradation in the photochromic properties of the glass taking place. The process includes the steps of forming a batch of specified components which include tin or a tin compound and subjecting the resultant batch to a series of glass-forming steps so as to develop photochromic properties in a glass article formed from the molten batch.The invention also provides a photochromic glass having silver halide crystals and tin dispersed throughout the glass, the glass having in its darkened state a brown coloration which is described in accordance with the Hunter L,a,b, Color Scale System by the rectangular region having corners defined by the (a,b) co-ordinates: (5,1), (1,5), (12,16) and (16,12), the 1/2 OD FT of the glass being 120 seconds or less.

Abstract: A polychromatic glass article, colored by silver, is disclosed wherein the silver occurs as an anisotropic film at the surface of lithium bromide spherulites which crystallize directly on silver nuclei from lithium silicate and lithium aluminosilicate glasses. The article is produced by sequential radiation exposures and heat treatments of the glass.

Abstract: The instant invention is directed to the production of highly polarizing glasses, i.e., the glasses exhibit dichroic ratios up to 40 and higher, from silver-containing glasses that are characterized as being phase separable or, more preferably, as being photochromic because of the presence of silver halide particles therein, i.e., particles selected from the group of AgCl, AgBr, and AgI. The inventive method contemplates two general steps:(a) the glasses are elongated under stress such that the glass phases and/or silver halide particles are elongated and aligned in the direction of the stress; and(b) the elongated glasses are heat treated in a reducing environment at temperatures below the annealing point of the glass but above about 300.degree. C. to reduce a portion of the silver ions in the glass to metallic silver which is deposited in at least one of the glass phases and/or along the phase boundaries of the glass phases and/or deposited upon the silver halide particles.

Abstract: Fast-response photochromic boro-silicate glasses which have a half-fading time of not more than 145 secs, have silver halide crystals dispersed throughout the glass and are free from barium, comprise, in weight percentages:SiO.sub.2 --31 to 59%B.sub.2 O.sub.3 --18 to 28%Al.sub.2 O.sub.3 --8 to 20%R.sub.2 O--6 to 16%wherein R.sub.2 O represents one or more of Li.sub.2 O, Na.sub.2 O and K.sub.2 O in amounts within the ranges 0 to 3% Li.sub.2 O, 0 to 8% Na.sub.2 O and 0 to 16% K.sub.2 O, and where the content of silver, expressed as Ag.sub.2 O, lies within the range 0.05 to 0.4% by weight, while the content of halide lies within the range 0.13 to 1% by weight of the glass.Further optional constituents are MgO (up to 2.6%) and P.sub.2 O.sub.5 (up to 12%). Refractive index n.sub.D can be corrected to the standard ophthalmic value of 1.523 by additions of ZrO.sub.2, TiO.sub.2 and/or PbO.