| abstract |
The invention relates to a glass composition for electric lamps comprising SiO2, Al2O3, Na2O, K2O, Li2O, B2O3, BaO, CaO and MgO, in addition optionally SrO, Sb2O3, MnO2, Fe2O3, and/or CeO2. The glass composition according to the invention is characterized in that its B2O3 content is 1 to 5 mass %, K2O content is 7.2 to 11 mass %, BaO content is 5.5 to 9 mass % and MgO content is 2.1 to 4 mass %, furthermore in addition to the components listed, it optionally also comprises maximum 3.5 mass % ZnO, maximum 1.2 mass % TiO2 and maximum 0.8 mass % P2O5 with the condition that the total amount of CaO, MgO and ZnO in the composition is at least 5.8 mass %. Stems and bulbs made of the above glass composition and used in electric lamps are also subject matters of the invention. |