| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass composition capable of realizing high dimentional accuracy and a glass quality level as a glass article which is secondarily thermally molded and to provide its manufacturing method. SOLUTION: The glass composition is composed of a multicomponent inorganic oxide, and a gas component having≥10 kPa vapor pressure and contained in the glass of 1 g mass is≤70μL (0°C, 1 atm), helium is in the range of 0.0001μL/g to 0.05μL/g (0°C, 1 atm) and a temperature at which viscosity of the glass becomes 10<SP>7.65</SP>dPa×s is≤900°C. The manufacturing method has a step of mixing and charging a glass raw material, a step of melting the glass raw material mixture M into a molten glass in a heat resistant vessel 30, a step of introducing helium B in a prescribed quantity to the molten glass G and a step of preparing the gas component having≥10 kPa vapor pressure contained in the glass to≤70μL/g (0°C, 1 atm) by discharging the gas component of a prescribed quantity from the molten glass G. COPYRIGHT: (C)2005,JPO&NCIPI
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