| 摘要 |
Provided is optical glass that does not contain lead, which is an environmental pollutant. The optical glass is ideal for the transmission of light even after being exposed to X-rays, and has a high refractive index. The optical glass comprises, by mass% in terms of oxide versus the glass total mass, 1.0% to 60.0% of an SiO 2 component, and one or more selected from the group consisting of an La 2 O 3 component, ZrO 2 component, TiO 2 component, Nb 2 O 5 component, and Ta 2 O 5 as essential components. The optical glass has a refractive index (n d ) of 1.50 or greater, and has a light intensity recovery rate of 45% or greater when the glass having been irradiated with X-rays with a dose of 2.5 Gy is irradiated with light of a xenon lamp for 11 hours. |
