Abstract: A method of preventing tarnishing of a polished glass article comprising storing the polished glass article under a reduced pressure of less than 10.sup.-2 mm Hg before applying a metal, a metal oxide or fluoride coating to the surface of the polished glass.

Abstract: A phosphate base laser glass comprising 55-70% P.sub.2 O.sub.5, 1-15% Al.sub.2 O.sub.3, 0-25% Li.sub.2 O, 0-25% Na.sub.2 O, 0-8% K.sub.2 O, the total proportion of Li.sub.2 O, Na.sub.2 O, and K.sub.2 O being 10-25%, 0-15% BaO, 0-15% ZnO, 0-15% CaO, 0-15%, SrO, 0-15% MgO, the total proportion of BaO, ZnO, CaO, SrO, and MgO being 5-15%, 0-5% Y.sub.2 O.sub.3, 0-5% La.sub.2 O.sub.3, 0-5% GeO.sub.2, 0-5% CeO.sub.2, 0-3% Nb.sub.2 O.sub.5, 0-3% MnO.sub.2, 0-2% Ta.sub.2 O.sub.5, 0-1% Sb.sub.2 O.sub.3, and 0.01-5% Nd.sub.2 O.sub.3, all % being mole %.The phosphate base laser glass of this invention has a high induced emission cross section, a low non-linear refractive index coefficient, and excellent acid resistance and divitrification resistance. By replacing partially or wholely one or more of LiO.sub.2, Na.sub.2 O, K.sub.2 O, BaO, ZnO, CaO, SrO, MgO or Al.sub.2 O.sub.3 by LiF, NaF, KF, BaF.sub.2 ZnF.sub.2, CaF.sub.2, SrF.sub.2, MgF.sub.2 or AlF.sub.

Abstract: A process for producing a soft aperture filter having high acid and heat resistance as well as a desired colored layer thickness comprising heat-treating a glass, having a base composition of 55 to 72 mole percent SiO.sub.2, 15 to 35 mole percent Na.sub.2 O, 0 to 5 percent di-valent oxides other than ZnO, 4 to 15 mole percent ZnO, and 0 to 5 mole percent Al.sub.2 O.sub.3 with Sb.sub.2 O.sub.3 and/or As.sub.2 O.sub.3 additionally present in an amount of 2 to 5 weight percent of the base composition, in a fused bath containing 14 to 60 mole percent of a silver salt, and optionally with NaNO.sub.3 and/or Na.sub.2 SO.sub.4.

Abstract: An optical fiber comprising a core glass and a cladding glass therearound, wherein at least the core glass contains GeO.sub.2 as an additive to increase the refractive index with respect to the cladding glass. The fiber glass is prepared by heat treating a starting glass to separate out a B.sub.2 O.sub.3 --Na.sub.2 O-rich phase for subsequent acid leaching, and by sintering a residual glass with low concentrations of light absorbing impurities. Ingredients of the starting glass in weight percent are as follows:SiO.sub.2 :25 - 80B.sub.2 o.sub.3 :10 - 30Na.sub.2 O:3 - 12GeO.sub.2 :3 - 40A1.sub.2 o.sub.

Abstract: Glass-based soft-edged aperture filters having good thermal stability are produced by diffusing a coloring element such as Ag into a glass, thus providing a transmittance gradient in the colored portion thereof. A glass composition comprising a basic glass, such as a silicate, borosilicate or phosphate glass, and 1 to 10% by weight of As.sub.2 O.sub.3 and/or Sb.sub.2 O.sub.3 is especially suitable for producing such soft-edged aperture filters.

Abstract: A glass composition for an ophthalmic lens having a refractive index of at least 1.69, an Abbe value of at least 39 and a specific gravity of not more than 3.2 and comprising, in percent by weight:1. 42 to 52 SiO.sub.2 +Al.sub.2 O.sub.3 +B.sub.2 O.sub.3 with 20 to 42 SiO.sub.2, 5 to 13 Al.sub.2 O.sub.3 and 0 to 20 B.sub.2 O.sub.3 ;2. 22 to 39 CaO+MgO with 12 to 39 CaO and 0 to 20 MgO;3. 15 to 28 ZrO.sub.2 +TiO.sub.2 +Nb.sub.2 O.sub.5 with 0 to 7 ZrO.sub.2, 5 to 13 TiO.sub.2 and 0 to 15 Nb.sub.2 O.sub.5 ;4. 0 to 15 BaO+SrO+ZnO with 0 to 6 BaO, 0 to 10 SrO and 0 to 15 ZnO; and5. 0 to 10 La.sub.2 O.sub.3 +Ta.sub.2 O.sub.5 +WO.sub.3 with 0 to 10 La.sub.2 O.sub.3, 0 to 6 Ta.sub.2 O.sub.5 and 0 to 10 WO.sub.3.

Abstract: This invention provides an anomalous dispersion glass exhibiting an .eta. d value of 1.54-1.71 and an.nu. d value of 55-30, and the anomaly of a partially dispersing property in the long wave length region. The anomalous dispersion glass contains B.sub.2 O.sub.3 45-70 mol.%; Pb0 5-30 mol.%; Na.sub.2 O 1-15 mol.%; SiO.sub.2 0-10 mol.%; Al.sub.2 O.sub.3 5-25 mol.%; one or more of CaO, BaO, MgO and CdO 0-16 mol.%, and one of TiO.sub.2, ZrO.sub.2, Sb.sub.2 O.sub.3, Wo.sub.3 and Tl.sub.2 O 0-3 mol.%. Fluorine may be present in an amount such that the F/O ion ratio in the resulting glass lies in the range of 0-0.35.

Abstract: A non-crystalline substance for use in an optical memory device which consists of an As-Se system non-crystalline material and the additional third component(s) Zn, Au, or Ag and/or Cu. The substance is characterized by its transmission ability in the visible region as well as in the I.R. region and its extreme reduction of transmittance upon irradiation with, e.g., a laser beam.

Abstract: A reversible light sensitive glass comprising 100 parts of a base glass, 0.15 to 1.0 parts of Ag and an amount of halogen corresponding to or more than to the chemical equivalence of Ag, in which the base glass consists of, by weight %, SiO.sub.2 48 to 62, Al.sub.2 O.sub.3 7 to 15, B.sub.2 O.sub.3 17 to 26, R.sub.2 O (where R represents Na, Li or K) 6 to 16, BaO 0.5 to 5, (BaO/R.sub.2 O 0.05 to 0.40), TiO.sub.2 0 to 10, ZrO.sub.2 0 to 10, Nb.sub.2 O.sub.5 0 to 5, TiO.sub.2 +ZrO.sub.2 +Nb.sub.2 O.sub.5 0.5 to 15, AS.sub.2 O.sub.3 0 to 2.0, and Sb.sub.2 O.sub.3 0 to 2.0 (AS.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 <2.0).

Abstract: A reversible light-sensitive glass comprising 100 parts of a base glass composition consisting, in weight percent, of 48 to 62% SiO.sub.2, 15 to 22% B.sub.2 O.sub.3, 0 to 7% Al.sub.2 O.sub.3, 0 to 10% ZrO.sub.2, 6<Al.sub.2 O.sub.3 + ZrO.sub.2 <12%, 6 to 16% R.sub.2 O where R represents Li, Na or K, 0.5 to 7% BaO, BaO/R.sub.2 O 0.035 to 0.65, 0 to 2% TiO.sub.2, and 0.002 to 0.03% CuO, and as light-sensitive components, 0.15 to 1.0 part of Ag and more than the chemical Ag equivalent of halogens selected from the group consisting of Cl, Br and I.

Abstract: Glass for use as an element of a Faraday rotator, consisting essentially of, by mol%, 10-30 Tb.sub.2 O.sub.3, 10-30 Al.sub.2 O.sub.3, and 30-80 SiO.sub.2 + B.sub.2 O.sub.3, with the proviso that SiO.sub.2 .gtoreq.15 and B.sub.2 O.sub.3 .gtoreq.10, and as optional components 0-5 ZrO.sub.2, 0-1 Sb.sub.2 O.sub.3, 0-1 As.sub.2 O.sub.3, and 0-2 AlF.sub.3. The glass has a large Verdet constant and a reduced absorption of light in the visible and infrared wavelength regions.

Abstract: A sealing method for a laser glass which provides a high bonding strength comprising applying a powder mixture of (1) a low melting glass for sealing a glass laser and (2) a glass having a higher melting point and lower expansion coefficient than those of the low melting glass, to a laser glass and welding the powder mixture to the laser glass by heating.

Abstract: A sealing method for a laser glass which provides a high bonding strength comprising applying a powder mixture of (1) a low melting glass containing an infrared absorbing component and (2) a low expansion high melting glass containing an infrared absorbing component to a laser glass and welding the powder mixture to the laser glass by heating.

Abstract: A process for heat-bonding optical fibers comprising aligning a number of optical fibers in a mould with at least one of whose end surfaces is open and with end members slidable towards the inside of the mould from positions at which the end surfaces are open whereby a gas present among the optical fibers can be discharged, heating the optical fibers and evacuating the gas in the mould, closing the open end surfaces and applying pressure to the optical fibers through a press member and the end members, thereby heat-bonding the optical fibers; and an apparatus for heat-bonding optical fibers, comprising a mould with at least one of whose end surfaces is open, and including a press member as a wall of the mould, at least one end member provided for the end surfaces of the mould, and being capable of sliding inwardly along inclined surfaces of the press member upon application of a presssure on the press member.

Abstract: A thorium oxide-free B.sub.2 O.sub.3 --La.sub.2 O.sub.3 --Gd.sub.2 O.sub.3 --Ta.sub.2 O.sub.5 system optical glass is improved in stability to devitrification and in optical constants by introducing at least one of a divalent metal oxide such as ZnO, CdO, PbO, BaO, SrO, CaO, and MgO into the optical glass composition or replacing Ta.sub.2 O.sub.5 of the optical glass composition with a divalent metal oxide. If desired, the glass may be free of CdO.

Abstract: A process for producing a gas tight light transmitting optical fiber plate comprising arranging the optical fibers or bundles of the optical fibers in a die, heating and compressing the optical fibers at a temperature of between the transition point of the glass of the optical fibers and the softening point of the glass of the optical fibers thereby to weld the optical fibers together, and maintaining the welded optical fibers within that temperature range at a pressure higher than the pressure during the heating period which is sufficient to cause the shrinkage of voids by the surface tension of the optical fibers.

Abstract: A reversible light-sensitive glass, e.g., for eyeglasses, comprising 100 parts of a base glass composition consisting, in weight percent, of 48 to 62% SiO.sub.2, 15 to 22% B.sub.2 O.sub.3, 0 to 11% Al.sub.2 O.sub.3, 0 to 10% ZrO.sub.2, 6<Al.sub.2 O.sub.3 + ZrO.sub.2 <13%, 6 to 16% R.sub.2 O where R represents Li, Na or K, 0.5 to 7% BaO, BaO/R.sub.2 O 0.035 to 0.65, 0 to 2% TiO.sub.2, 0 to 2.5%Nd.sub.2 O.sub.3, 0 to 2.5% Ho.sub.2 O.sub.3, 0 to 2.5% Er.sub.2 O.sub.3, 0.2<Nd.sub.2 O.sub.3 + Ho.sub.2 O.sub.3 + Er.sub.2 O.sub.3 <2.5% and 0.002 to 0.03%CuO, and as light-sensitive components 0.15 to 1.0 part of Ag and more than the Ag chemical equivalent of halogens selected from the group consisting of Cl, Br and I.