PURPOSE: To obtain a glass, containing additives, and having improved light transmitting property, by forming an assembly of fine glass particles having a lower viscosity in the outer surface than in the interior, and sintering the resultant formed material.
CONSTITUTION: In preparing a glass containing nitrogen, fine particles 10 of Si2N3 are first prepared, and the outer surface layers 11 are formed on the outer surfaces of the fine particles 10. The resultant coated fine particles 10 are then sintered to prepare quartz glass 12 containing the nitrogen. A low-molecular gas, inert to the glass component e.g. He is used as the sintering atmosphere to diffuse into the glass easily and make the glass 12 transparent without remaining in the glass as bubbles. The sintering temperature is preferably 700W 1,200°C.
TANAKA GOUTAROU
HOSHIKAWA MASAO
FUJIWARA KUNIO
WATANABE MINORU
SUMITOMO ELECTRIC INDUSTRIES