| 摘要 |
The principal object of the present invention is organic lens molds, constituted wholly or in part of at least one specific inorganic glass, advantageously strengthened by a chemical tempering or a thermal tempering. Said glass has the following composition, expressed in percentages by weight: SiO2 56-66, Al2O3 2.5-10, B2O3 0.5-7, Li2O 0-3, Na2O 8-15, K2O 3-12, with Li2O+Na2O+K2O 12-20, ZnO 2-12, MgO 0-3, TiO2 0-0.5, ZrO2 1-9, CaO 0-1, BaO 0-2, SrO 0-2, with MgO+CaO+SrO+BaO 0-5, Cl 0-0.5, As2O3+sb2O3 0-1. The invention also deals with novel inorganic glasses which have the above composition with a single exception relative to the Al2O3 content: Al2O3 2.5-4. |
