摘要 |
In order to produce a fluorophosphate glass including P5+ at a small content on the composition thereof, the composition is adjusted so as to provide well-balanced chemical durability and thermal stability. In the production of a fluorophosphate glass in which O2−/P5+>3.7, Al3+ content is in a predetermined amount or more and p5+ content is in a predetermined amount or less, a glass raw material is prepared by using an AlF3 in which the content of Al2O3 is limited to the range from 1 to 5% by mass, and the raw material is melted to produce the fluorophosphate glass. |