Lamp having a glass lamp vessel and Glass (Na-Ca-Ba-SiO2 with B2O3/Al2O3/ZrO2) suitable therefor

摘要

The invention relates to lamps having a glass lamp vessel (1) and to a glass suitable therefor. The relevant glass is adequately resistant to attack by electrons, is resistant to atmospheric influences and is properly workable in a gas flame. This glass contains 44-60 mole % silicon oxide; 0-7.5 mole % boron oxide; 0-6 mole % zirconium oxide; 0-7.5 mole % aluminium oxide; 5-20 mole % calcium oxide; 12.5-25 mole % barium oxide; 0-15 mole % magnesium oxide; 0-10 mole % strontium oxide; 2-8 mole % sodium oxide. The sum of the alkaline earth metals is 25-42.5 mole %. No discoloration occurs in sodium vapor discharge lamps when the lamp vessel has been made of this glass.