This invention is directed to glasses exhibiting annealing points above 625.degree. C., strain points above 600.degree. C., linear coefficients of thermal expansion (25.degree.-300.degree. C.) below 90.times.10.sup.-7 /.degree. C., refractive indices below 1.8, and, in thicknesses of 2 mm, infrared transmissions of at least 50% to wavelengths longer than 6 .mu.m, consisting essentially expressed in terms of cation % on the oxide basis, of 5-40% KO.sub.0.5, 4-22% LaO.sub.1.5, 50-76% GaO.sub.1.5, and up to 15% total of at least one additional component in the indicated properties selected from the group consisting of______________________________________ BaO 0-5 NaO.sub.0.5 0-5 CaO 0-5 PbO 0-5 CsO.sub.0.5 0-10 ZnO 0-5 ReO.sub.1.5 0-5 Cl 0-5. ______________________________________