| 摘要 |
The present invention provides a fluorophosphate glass containing phosphorus, oxygen and fluorine as glass ingredients, in which, provided that a refractive index nd of the glass is nd (1) and a refractive index nd after re-melting the glass at 900°C for 1 hour in a nitrogen atmosphere, cooling the glass to a glass transition temperature and then cooling the glass down to 25°C at a temperature decrease rate of 30°C per hour is nd (2) , an absolute value of a difference between nd (1) and nd (2) (nd (2) -nd (1) ) is equal to or less than 0.00300, and a molar ratio (O 2- /P 5+ ) of a content of O 2- to a content of P 5+ is equal to or more than 3.5. The glass of the invention is reduced in volatility and erosiveness. |
