An alumino earth-alkali silicate glass for lamp bulbs of tungsten halogen incandescent lamps has the following glass composition (% by weight) that reduces discoloration during operation of the lamp bulb: TABLE-US-00001 SiO.sub.2 55.0 62.5 Al.sub.2O.sub.3 14.5 18.5 B.sub.2O.sub.3 0.8 4.0 BaO 7.5 17.0 CaO 6.5 13.5 MgO 1.0 5.5 SrO 0 2.0 ZrO.sub.2 0 1.5 TiO.sub.2 0 1.0 ZnO 0 0.5 CeO.sub.2 0 0.3 R.sub.2O <0.03 H.sub.2O 0.025 0.042.