| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical glass with a high refractive index excellent in devitrification resistance both in a melting state and at re-heating, a glass raw material for press molding containing the optical glass, and an optical element.SOLUTION: There is an optical glass containing, by mass%, BOand SiOof the total 15 to 37%, TiO, NbOand ZrOof the total 15 to 45%, BaO, SrO, CaO, MgO, KO, NaO and LiO of the total 12 to 40%, and having a mass ratio (BO/(BO+SiO)) of 0.15 or more, the mass ratio (TiO/(TiO+NbO+ZrO)) of 0.01 to 0.8, the mass ratio of ((BaO+SrO+CaO)/(BaO+SrO+CaO+MgO+KO+NaO+LiO)) of 0.4 or more, and the mass ratio ((KO+NaO+LiO)/(BaO+SrO+CaO+MgO+KO+NaO+LiO)) of 0.1 or more, and containing practically no PbO, and having a refractive index nd of 1.78 to 1.84 and an Abbe number &ngr;d of 26 to 32. |
