Abstract: An optical and ophthalmic glass with high refractive index, high Abbe number and low density, which is distinguished by good chemical stability, good crystallization behavior and capability of chemical hardening, comprises (in % by weight):______________________________________ SiO.sub.2 50-63 B.sub.2 O.sub.3 4-8 Al.sub.2 O.sub.3 1-2 Li.sub.2 O 4-8 Na.sub.2 O 4-8 K.sub.2 O 3-7 sum of M.sub.2 O 11-20 (M = Li, Na, K) MgO 0.5-2 CaO 2-5 sum of MO 0-3 (M = Mg, Ca) TiO.sub.2 8-12.5 ZrO.sub.2 1-3 F.sup.- 0-1 As.sub.2 O.sub.3 0.05-0.15 (optional refining agent) Sb.sub.2 O.sub.3 0.0-0.

Abstract: An optical and ophthalmic glass with high refractive index, high Abbe number and low density, which is distinguished by good chemical stability, good crystallization behavior and capability for chemical hardening, comprises (in % by weight):SiO.sub.2 --47 to 75B.sub.2 O.sub.3 --1 to 20Al.sub.2 O.sub.3 --0 to 10P.sub.2 O.sub.5 --0 to 5Li.sub.2 O--0 to 15Na.sub.2 O--0 to 10K.sub.2 O--0 to 10CaO--0 to 20MgO--0 to 15SrO--0 to 4BaO--0 to 4ZnO--0 to 5TiO.sub.2 --1 to 15ZrO.sub.2 --0 to 8Nb.sub.2 O.sub.5 --0 to 5 andF----0 to 5.

Abstract: A spectacle glass which is colorless in the visible spectrum range, not transmissive in the ultraviolet spectrum range below 350 nm, has a refractive index n.sub.d higher than 1.56 and an Abbe number of more than 45, and which has an extremely low density, has the following composition (in % by weight):______________________________________ 12-40 P.sub.2 O.sub.5 13-34 Al.sub.2 O.sub.3 8-30 SiO.sub.2 0-16 B.sub.2 O.sub.3 4-12 TiO.sub.2 0-4 ZrO.sub.2 2-18 CaO 0-4 MgO 0-15 Na.sub.2 O 0-11 K.sub.2 O 0-6 Li.sub.2 O 0-12 Nb.sub.2 O.sub.5 0-8 ZnO.

Abstract: An optical fiber comprising a light-conducting core and a borosilicate glass optical insulation cladding thereon is stabilized against the effects of nuclear radiation by incorporating in the core and the cladding an amount of Sb.sub.2 O.sub.3 effective to harden the fiber against nuclear radiation. Amounts of 0.002-6 wt. % Sb.sub.2 O.sub.3 are generally useful.

Abstract: In a process for the production of communication fibers having transmission losses of less than 10 db/km. and a pulse dispersion of less than 4 ns/km., both measured at 860 nm, by the internal cladding method, wherein multiple-component glasses are deposited in layers in the glassy state in the interior of a glass tube; the tube thus clad inside, is collapsed to a rod; and the rod is drawn into a fiber, the core diameter of which has an eccentricity of less than 2%, an improvement is provided wherein a precollapsing step is executed prior to the final collapsing process, the precollapsing step occurring during the internal cladding step. The temperature of the cladding step is greater than 1850.degree. C. and above the softening point of the glass tube.

Abstract: Optical fibers having high infrared transmittancies are produced by chemical vapor deposition of vitreous layers composed predominantly of anions S, Se and/or Te onto tubes or rods. Cations are Ge, Si, P, B, As, Sb and/or Ti. Conventional CVD techniques are employed to produce stepped-refractive index gradient profiles in the fibers except that an inert gas and/or a halogen(s) is used as the propellant gas.

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: 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.