Abstract: A phototropic glass containing P.sub.2 O.sub.5 as the principal component and, as agents imparting phototropy, silver and halogen in non-crystalline form.

Abstract: For producing gradient refractive index optical components having substantially no internal stress, there is provided for the ion exchange step glass of the following composition______________________________________ SiO.sub.2 47 - 61 CaO 0 -5 Al.sub.2 O.sub.3 13 - 20 Li.sub.2 O 3 - 10 La.sub.2 O.sub.3 1 - 8 Na.sub.2 O 6 - 16 Ta.sub.2 O.sub.5 0 - 7.5 K.sub.2 O 0 - 6 ZrO.sub.2 0 - 4 PbO 0.5 - 15 WO.sub.3 0 - 3 TiO.sub.2 0 - 4 BaO 0 - 5 P.sub.2 O.sub.5 0 - 3 ZnO 0 - 5 B.sub.2 O.sub.3 0 - 5 MgO 0 - 5 Fining Agent.

Abstract: A process for the treatment of glass to modify various properties thereof. The process comprises the steps of applying a coating of at least one metal, preferably by vapor deposition, onto the surface of a SiO.sub.2 containing glass. The coated glass is thereafter heated to a temperature sufficient to cause the metal to migrate from the surface of the glass into the glass without any residue or coating remaining on the surface of the glass.

Abstract: Glass as near-portion material for fusion with known phototropic far-portion glasses for multifocal spectacle lenses has a linear thermal expansion coefficient between 45 and 58 .times. 10.sup.-.sup.7 /.degree. C, a refractive index of n.sub.d .gtoreq.1.60, a speed of crystallization of less than 0.5 .mu./min., and the following composition:______________________________________ SiO.sub.2 10.0 - 20.0 % by weight B.sub.2 O.sub.3 15.0 - 23.0 % by weight PbO >26.0 - 30.0 % by weight ZnO 3.0 - 5.0 % by weight La.sub.2 O.sub.3 6.0 - 10.0 % by weight Al.sub.2 O.sub.3 12.0 - 17.0 % by weight ZrO.sub.2 0.5 - 3.0 % by weight TiO.sub.2 0.2 - 3.0 % by weight K.sub.2 O 0.1 - 2.0 % by weight Na.sub.2 O 0.1 - 2.0 % by weight Li.sub.2 O 0.1 - 4.0 % by weight ______________________________________With the provision that: ______________________________________ sum of SiO.sub.2 + B.sub.2 O.sub.3 is 30.0 - 40.0 % by weight sum of the alkali oxides is 0.2 - 3.0 % by weight sum of Al.sub.2 O.sub.3 + La.sub.2 O.sub.3 is 19.

Abstract: The mechanical strength of glass is improved by applying a fluid epitaxially active crystalline primary layer to a glass plate consisting of a glass inclined to crystallization. The glass plate with the mentioned fluid layer thereon is subjected to a temperature treatment to cause a reaction between the glass plate and the primary layer. During this reaction, the primary layer is effective to cause in and near the surface of the glass plate an elimination of at least a portion of the crystals which have a smaller thermic expansion coefficient than the starting glass of the glass plate.

Abstract: A chemically hardened optical crown glass having a refractive index n.sub.d of 1.5225-1,5235, a thermal expansion coefficient in the temperature range between 20.degree. and 300.degree. C. of 90 .times. 10.sup.-.sup.7 to 100 .times. 10.sup.-.sup.7 /.degree.C., a dispersion .gamma.d of 54-60, a softening temperature of 690.degree.-750.degree. C., and a transformation temperature of 480.degree.-550.degree. C., produced by melting, shaping and cooling a batch consisting essentially of the following composition in parts by weight based on 100 parts of total composition: SiO.sub.2, 50.5-61.0; Al.sub.2 O.sub.3, 7.0-17.5; B.sub.2 O.sub.3, 2.0-6.1; Li.sub.2 O, 0-1.0; Na.sub.2 O, 12.0-15.0; K.sub.2 O, 2.5-3.5; CaO, 0-4.1; BaO, 0-0.3; ZnO, 5.0-10.0; PbO, 0-0.5; TiO.sub.2, 0.1-0.9; As.sub.2 O.sub.3, 0-0.5; and Sb.sub.2 O.sub.3, 0-1.

Abstract: An article comprising a substrate forming a body portion of the article and a reversible phototropic coating thereon, the coating comprising a glassy or crystalline composition of the system Me.sup.a .sup.+, X, Me.sup.b .sup.+ wherein:Me.sup.a .sup.+ is a photosensitive metal of valence a.sup.+,X is an anion, andMe.sup.b .sup.+ is a metal of valence b.sup.+Me.sup.a .sup.+, X, and Me.sup.b .sup.+ being compatible in proportion to provide said reversible phototropic coating. Typically Me.sup.a .sup.+ is Ag.sup.1 .sup.+, Cd.sup.2 .sup.+, Hg.sup.2 .sup.+, or Pb.sup.2 .sup.+; X is a halogen anion; and Me.sup.b .sup.+ is Pb.sup.2 .sup.+, Zn.sup.2 .sup.+, Sn.sup.4 .sup.+, Tl.sup.3 .sup.+, an alkali metal cation or an alkali earth metal cation.

Abstract: Photochromic glass compositions are photochromically activated by immersion in a hot liquid bath at activation and/or annealing temperatures to provide improved thermal efficiency and control of the degree of activation, making possible the rapid production of uniform photochromic glass products. The hot liquid bath is a molten salt bath having a density very close to that of the glass composition. A silver salt may be employed in the salt bath to prevent silver diffusion from the glass, the required amount of silver being already present in the glass prior to its immersion in the salt bath. The glass is not simultaneously ion exchanged during the annealing process in order to tint and/or strengthen the glass. Coloring may be effected.

Abstract: A transparent phototropic laminate comprising a light transmitting substrate, a inorganic phototropic layer attached to the substrate and a polymeric layer attached to the phototropic layer.