Abstract: A phosphate optical glass, whose length of the light path is substantially independent of temperature, comprising, in % by weight,______________________________________ P.sub.2 O.sub.5 27 - 55 K.sub.2 O 6 - 26 BaO 10 - 50 K.sub.2 O + BaO larger than 35 Al.sub.2 O.sub.3 2 - 15 TiO.sub.2 + Nb.sub.2 O.sub.5 + Ta.sub.2 O.sub.5 4 - 20 TiO.sub.2 0 - 14 Nb.sub.2 O.sub.5 0 - 20 Ta.sub.2 O.sub.5 0 - 7 B.sub.2 O.sub.3 0 - 5 Li.sub.2 O 0 - 2 Na.sub.2 O 0 - 5 MgO 0 - 6 CaO 0 - 8 SrO 0 - 10 ZnO 0 - 10 PbO 0 - 13, and As.sub.2 O.sub.3 0 - 2 .

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: 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: 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 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 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 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.