Abstract: The present invention relates to glasses of high refractive index having the following composition of oxides, expressed in percentages by weight: SiO2 27-36 B2O3 0-9 Li2O 1-5 Na2O 1-7 K2O 0-7 CaO 0-7 BaO  4-13 ZnO 0-8 La2O3  4-15 PbO  4-27 TiO2  7-18 ZrO2 0-9 Nb2O5 0-8 with: Li2O + Na2O + K2O  6-15 SiO2 + TiO2 + ZrO2 42-55 PbO + TiO2 + ZrO2 + Nb2O5 29-40; their use for the production of segments for multifocal corrective lenses; and multifocal corrective lenses incorporating at least one such segment in their structure.

Abstract: An ophthalmic, protective, filter lens, and a method of producing such lens, the lens having a ratio of Z and Y tristimulus values between 0.25-0.40, a dominant wavelength between 570-580 nm. on a color mixture diagram, a sharp transmission drop between 450-500 nm. and a transmission not over 30% between 400-450 nm.

Abstract: A family of alkali-tungsten-tellurite glasses that consist essentially of, as calculated in mole percent, 10-90% TeO2, at least 5% WO3 and at least 0.5% R2O where R is Li, Na, K, Cs, Tl and mixtures, that may contain a lanthanide oxide as a dopant, in particular erbium oxide, and that, when so doped, is characterized by a fluorescent emission spectrum having a relatively broad FWHM value.

Abstract: The present invention relates to: a method of bending the perimeter of at least one opening (2) provided in a glass-ceramic precursor plate (1), said perimeter describing a closed curve without sharp angles; a method of manufacturing a glass-ceramic plate (10′, 10″) in which at least one opening (2) is provided, whose perimeter describing a closed curve without sharp angles is bent; novel glass-ceramic plates (10′, 10″), obtainable by implementing said manufacturing methods.

Abstract: This invention relates to lead-free silicate glasses that find use in producing fine crystal glassware and in laminated ware applications. The glasses consist essentially, in weight percent, of: SiO2 52-66 ZnO 15-30 Al2O3 0-4 BaO 0-7 Li2O 0-4 MgO + CaO + SrO 0-4 Na2O  3-16 ZrO2 0-4 K2O  0-12 B2O3  0-4.

Abstract: A fixed tint, photochromic glasses and sunglass lenses produced therefrom. The glasses have R2O—Al2O3—B2O3—SiO2 base compositions, contain silver chloride and bromide contents as photochromic constituents and 0.27-0.38% and 0.035-0.060%, both by weight percent, as glass colorants, the NiO:Co3O4 ratio being at least 6:1.

Abstract: An article of relatively pure silica, and a furnace and method of producing the article. The article is produced by collecting molten silica particles (24) in a refractory furnace in which at least a portion of the refractory has been exposed to a halogen-containing gas to react with contaminating metal ions in the refractory.

Abstract: A fixed tint, photochromic glasses and sunglass lenses produced therefrom. The glasses have R.sub.2 O--Al.sub.2 O.sub.3 --B.sub.2 O.sub.3 --SiO.sub.2 base compositions, contain silver chloride and bromide contents as photochromic constituents and 0.22-0.38% NiO and 0.034-0.060% CoO, both by weight percent, as glass colorants, the NiO:CoO ratio being in the range of 5.5-7.2:1.

Abstract: The invention concerns photochromic glasses with improved properties having the following composition, in wt. %: SiO.sub.2 : 51-66, B.sub.2 O.sub.3 : 15-23, Al.sub.2 O.sub.3 : 3-10, ZrO.sub.2 : 2.5-11, TiO.sub.2 : 0-1, Li.sub.2 O: 3-7, Na.sub.2 O: 0-8, K.sub.2 O: 2-9, Ag: 0.080-0.30, CuO>0.0020-0.0130, Cl: 0.1-0.6, Br 0.040-0.3, MgO: 0-3, CaO: 0-3, SrO: 0-3, BaO: 0-3, Nb.sub.2 O.sub.5 : 0-1, La.sub.2 O.sub.3 : 0-8, Y.sub.2 O.sub.3 : 0-8, with 0.2<Ag/(Cl+Br).ltoreq.0.5, Br/(Cl+Br)>0.15, 0.5.ltoreq.La.sub.2 O.sub.3 +Y.sub.2 O.sub.3.ltoreq.8, TiO.sub.2 +Nb.sub.2 O.sub.5 .ltoreq.1.2, 10.ltoreq.Al.sub.2 O.sub.3 +ZrO.sub.2 .ltoreq.17, MgO+CaO+SrO+BaO.ltoreq.6. Use for the production of ophthalmic lenses.

Abstract: The present invention relates to a method of making a rectangular bar have a gradient composition. In optical or ophthalmic applications, the gradient of composition ensures formation of a corresponding gradient of optical property, such as refractive index or optical density. The glass material is manufactured using a device containing several reservoirs, all designed to contain glass in the fluid state. According to the invention, the composition of the glass varies from one reservoir to the other so that the refractive indices, for example, of the three compositions are different, with an incremental progression. The fluid glass is deposited one composition on top of the next and then heated, creating a certain degree of interdiffusion between the layers. The glass is then heat-treated to create the desired property profile.

Abstract: Nanocrystalline glass-ceramic materials based on .beta.-quartz solid solution Mg-rich phases formed in the system SiO.sub.2 --Al.sub.2 O.sub.3 --MgO--Li.sub.2 O--TiO.sub.2 (ZnO, BaO, ZrO.sub.2, P.sub.2 O.sub.5). Articles made from the glass-ceramic materials exhibit a crystal phase assemblage of a fine-grained, microstructure which is predominantly .beta.-quartz, and at least one additional phase selected from enstatite and spinel, and having a composition which consists essentially of, in weight percent on the oxide basis, 40-65% SiO.sub.2, 10-14% Al.sub.2 O.sub.3, 5-25% MgO, 0.5-4% Li.sub.2 O, 5-15% TiO.sub.2, and up to 5% ZrO.sub.2, such that the sum of (TiO.sub.2 +ZrO.sub.2) is at least 9% The glass-ceramide article is particularly useful for memory disk applications.

Abstract: The invention concerns glasses that have a refractive index of more than 1.880, an Abbe number of more than or equal to 30.4, and a density of more than 4.1, and having the following chemical composition, expressed in wt. %, based on the oxides: SiO.sub.2 : 6-9, B.sub.2 O.sub.3 : 15-19, with SiO.sub.2 +B.sub.2 O.sub.3 <26, Nb.sub.2 O.sub.5 : 12 to <20.5, ZrO.sub.2 : 8-10, TiO.sub.2 : 7-11, La.sub.2 O.sub.3 : 23-32, with ZrO.sub.2 +TiO.sub.2 +La.sub.2 O.sub.3 : .gtoreq.44, CaO: 8 to <13, SrO: 0-2, BaO: 0-2, MgO: 0-2, ZnO: 0-5, with CaO+SrO+BaO+MgO+ZnO: .gtoreq.9, Y.sub.2 O.sub.3 : 0-5, WO.sub.3 : 0-5, Li.sub.2 O+Na.sub.2 O+K.sub.2 O: 0-2, others 0-1.

Abstract: The invention relates to a method of making glass-ceramic plates which are bent at a radius of curvature especially suitable in the manufacture of cooking plates.

Abstract: A method of lessening the tendency of carbon to deposit on a hot metal surface, particularly a component in a furnace for thermally cracking hydrocarbons, that comprises coating a chromium-containing metal surface with a layer of porous, dry, pulverized glass and heating the coated metal to form an adherent, vitreous coating on the metal surface.

Abstract: A method of protecting a metal against embrittlement when the metal is exposed to carbon or sulfur at an elevated temperature, the method comprising forming a thin, adherent, continuous coating of a glass on the surface of the metal prior to exposure to carbon or sulfur at an elevated temperature.

Abstract: A method of controlling the rheology of a sealing glass paste which comprises incorporating a fine inorganic powder in the paste as a mill addition to impart a steep rheology curve to the paste so that the paste resists flow while at rest, but flows readily when shear stress is applied, the amount of inorganic powder incorporated being not over about 10% by weight.

Abstract: The material is in a fluid state at a predetermined temperature above the ambient temperature. According to the invention: a) at least two different compositions of this material in the fluid state are prepared; b) simultaneously and concentrically both the core of the rod with the aid of one of the compositions and a sheath enveloping this core with the aid of another composition are cast; and c) the casting is then taken to a temperature at which it solidifies to constitute the rod. Advantageously, the section of the casting is made to grow by its passing through a cylindrical mold shaped to define the final section of the rod. Application to the manufacture of a glass rod presenting a cross-sectional refractive index gradient.

Abstract: A protective coating which imparts non-stick and abrasion resistant properties, as well as hydrophobic properties to an inorganic article, the coating being the composition product between hydroxyl groups on the surface of the inorganic article and a composition comprising a silane, a metal alkoxide and an acidified aqueous mixture of a lower alkanol. The silane content is at least 50% of the total sum of the silane plus the metal alkoxide. The metal alkoxide is at least 5% and preferably 10% of the total sum of the silane plus the metal alkoxide.

Abstract: A fusion sealing material, and a fusion seal prepared therefrom, consisting essentially of at least 65% of a SnO--ZnO--P.sub.2 O.sub.5 glass fit, up to 10% of a crystallization catalyst and 0-25% of an additive that decreases the effective CTE of a seal prepared with the material.

Abstract: The invention relates to brown glasses which absorb ultraviolet radiation that are used in the production of ophthalmic sun glasses, and that have the following composition, expressed in wt. %:______________________________________ SiO.sub.2 59-78 Al.sub.2 O.sub.3 2-6 B.sub.2 O.sub.3 0-3 Na.sub.2 O 7-16 K.sub.2 O 2-9 CaO 0-7 BaO 0-12 ZnO 0-12 ZrO.sub.2 0-6 TiO.sub.2 0-6 MnO.sub.2 0.25-6 V.sub.2 O.sub.5 1-3 Fe.sub.2 O.sub.3 0-1.5 NiO 0-0.5 CoO 0-0.1 Sb.sub.2 O.sub.3 0-0.7 As.sub.2 O.sub.3 0-0.7 F 0.05-1.0 With MnO.sub.2 + Fe.sub.2 O.sub.3 + V.sub.2 O.sub.5 >1.5 Al.sub.2 O.sub.3 + SiO.sub.2 .gtoreq.65.