Abstract: An optical glass having n.sub.D =1.63.+-.(1.5.times.10.sup.-2), v.sub.D =59.5.+-.1.0, a high chemical stability and a low tendency to crystallization is provided, consisting essentially of (in percent. by weight):______________________________________ SiO.sub.2 23-27 B.sub.2 O.sub.3 24-30 SrO 18-31 La.sub.2 O.sub.3 10-16 Al.sub.2 O.sub.3 2-4 BaO 0-10 CaO 0-5 ZnO 0-6 Y.sub.2 O.sub.3 0-5 ZrO.sub.2 0-2 Li.sub.2 O, Na.sub.2 O and/or K.sub.2 O 0-1.5 As.sub.2 O.sub.3 and/or Sb.sub.2 O.sub.3 0-1 F and/or Cl 0-1, ______________________________________wherein the sum of SiO.sub.2 +B.sub.2 O.sub.3 is 50-53, the weight ratio SiO.sub.2 :B.sub.2 O.sub.3 is 0.8-1.0, the sum SrO+BaO is 26-31, and the sum ZnO+La.sub.2 O.sub.3 is 12-17.

Abstract: Glass composition ranges are described which permit the introduction of laser activators into fluorphosphate glass with exceptionally high fluorine content while forming glasses of high crystallization stability and permitting the realization of large melt volumes. The high fluorine content imparts to the glasses an exceptionally low nonlinear refractive index n.sub.2 down to O,4 .times.10.sup.-13 esu.

Abstract: Optical glasses having high refractive indexes and low specific gravities are provided for use as both distant and near vision spectacle lenses. The glasses consist essentially of low molecular weight cationic oxides, alkali metal oxides and divalent oxides to promote the crystallization stability of the glass. They have good chemical resistance, chemical hardenability and a thermal expansion coefficient between 93 and 99.times.10.sup.-7 /.degree. C. in the range of 20.degree.-300.degree. C. Optical lenses can be continuously produced due to the high crystallization stability of the glasses and the resultant spectacle lenses have high dioptric values even with thinner edge or center thicknesses.

Abstract: A glass having a high refractive index, preferably >1.77, and a low specific gravity, preferable .ltoreq.3.8, is provided for utilization as spectacle lenses. The glass consists essentially of 80 mol percent or more of light cationic oxides with the remainder being cationic oxides having a greater molecular weight. It has a high crystallization stability in a viscosity range >200 poises and an expansion coefficient .alpha..times.10.sup.7 between 20.degree.-300.degree. C. of .ltoreq.100. Sufficiently light in weight to be well-suited for use as spectacle lenses, the glass can be continuously produced, as it has no pronounced tendency toward crystallization. The resulting corrective optical lenses have relatively high dioptric values, even with small center and edge thicknesses.

Abstract: Glasses are provided which may be made phototropic and which have a thermal coefficient of linear expansion between about 43 and 58.times.10.sup.-7 /.degree. C. and an index of refraction n.sub.d over about 1.60. Such glasses can be employed as near portion glass material in spectacle lens manufacture; thus, such glasses can be fused with known phototropic for portion glass material, for example, of the borosilicate type, to make multifocal glasses useful in spectacle lenses and spectacles.

Abstract: A glass when in the form of an optical fiber having an optical loss of not more than 150 dB/km, high transparency, a high numerical aperture, and a high flexural strength, said glass being especially suitable for optical fibers and consisting essentially of:SiO.sub.2 : 65 - 75 mol-%; (38 - 46% by weight);R.sub.2 o: 4 - 17 mol-%; (4 - 13% by weight);PbO: 16 - 25 mol-%; (42 - 55% by weight); wherein R.sub.2 O is Na.sub.2 O, K.sub.2 O or Cs.sub.2 O or mixtures thereof, preferably not more than 3.0 mol % Na.sub.2 O, and with the provision that the molar ratio of SiO.sub.2 : PbO is 2.5 - 4.0.

Abstract: An optical glass with a path length independent of temperature comprises between 40 and 55% by weight P.sub.2 O.sub.5, between 40 and 54% by weight BaO and between 6 and 12% by weight Nb.sub.2 O.sub.5. Part of the BaO may be replaced by SrO or CaO. Minor amounts of SiO.sub.2 or B.sub.2 O.sub.3 may be included as may other metal oxides such as ZnO, Sb.sub.2 O.sub.3 and La.sub.2 O.sub.3.

Abstract: Optical, fluorine containing barium borosilicate glasses having an improved varying partial dispersion in the optical positional range of lanthanum crown and lanthanum flint glasses wherein the ratio of SiO.sub.2 with respect to SiO.sub.2 and B.sub.2 O.sub.3 is at least 0.62 and the content of fluorine in said glass is between 2 and 7 grams per 100 cc of said glass.

Abstract: A neodymium-doped phosphate laser glass composition having a low threshold for stimulated emission, a negative temperature coefficient of refractive index, high acid resistence and homogeneity even in large structures comprises P.sub.2 O.sub.5, Na.sub.2 O or K.sub.2 O, Al.sub.2 O.sub.3, Nd.sub.2 O.sub.3, and optionally, F or RO, wherein R is Mg, Ba, Ca, Sr or Zn.

Abstract: Optical glass with a path length independent of temperature includes SiO.sub.2, B.sub.2 O.sub.3, K.sub.2 O, BaO, ZrO.sub.2, TiO.sub.2, Nb.sub.2 O.sub.5, P.sub.2 O.sub.5 and F in specified percentages by weight, with the sum of the amounts of SiO.sub.2, B.sub.2 O.sub.3 and P.sub.2 O.sub.5 between 38 and 45% by weight and the sum of the amounts of ZrO.sub.2 and TiO.sub.2 between 12 and 27% by weight.

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: Optical glass, nd = 1.650 .+-. 2 .times. 10.sup..sup.-3 and vd = 55.5 .+-. 1.0, having a high chemical stability and a sufficiently low tendency toward crystallization that it can be manufactured in a continuous tank melting process into gobs, pressed components, and other formed articles as a mass-produced glass, said glass consisting essentially of, in percent by weight:SiO.sub.2 33.0 .+-. 0.5 B.sub.2 O.sub.3 11.6 .+-. 0.5 BaO 36.6 .+-. 1.0 La.sub.2 O.sub.3 14.0 .+-. 2.5 ZrO.sub.2 4.0 .+-. 2.5 As.sub.2 O.sub.3 0 - 0.5. or Sb.sub.2 O.sub.