FLUOROPHOSPHATE GLASS, PRECISION PRESS MOLDING PREFORM, OPTICAL ELEMENT BLANK, OPTICAL ELEMENT AND METHOD OF MANUFACTURING THE SAME

摘要

The present invention provides a fluorophosphate glass containing more than 3 cationic % and 30 cationic % or less of a phosphorus ingredient in terms of P5+, the glass having a ratio I(1)/I(0) of equal to or less than 0.08 in which I(0) is a strength of a resonance peak generated near a reference frequency of 31P in a nuclear magnetic resonance spectrum and I(1) is a strength of a first-order side band peak of the resonance peak. The glass of the invention is reduced in volatility and erosiveness.