METHOD FOR PRODUCING FLUOROPHOSPHATE GLASS, METHOD FOR PRODUCING GLASS MATERIAL FOR PRESS FORMING AND METHOD FOR PRODUCING OPTICAL ELEMENT

摘要

The objective of the present invention is to produce a fluorophosphate glass with a low P5+ content in the composition thereof which has a good balance between chemical resistance and thermal stability. That is, provided is a method for producing a fluorophosphate glass which is O2-/P5+=3.7, and which has a predetermined amount or more of Al3+ and a predetermined amount or less of P5+, by preparing a glass material using AlF3 in which the ratio of the amount of Al2O3 is limited to a range of 1-5 mass%, and melting this material.