Thallium-containing optical glass

摘要

A thallium-containing optical glass composition which comprises the following oxides in the indicated proportions in mole %: SiO2 35-80, Tl2O 1-30, Tl2O+R2O (R being an alkali metal) 1-35, ZnO 0-35, GeO2 0-30, BaO 0-25, TiO2 0-20, MgO 0-20, B2O3 0-less than 10, ZrO2 0-2, Al2O3 0-8, SnO 0-5, CaO 0-10, SrO 0-10, PbO 0-10, La2O3 0-5, Bi2O3 0-8, and Ta2O5 0-2, and satisfies the following relations: 5