| 摘要 |
PURPOSE:To produce a high quality glass article, especially glass for an optical fiber. CONSTITUTION:When a deposit of fine glass particles is synthesized by a vapor phase synthesis method and converted into transparent glass by heating in vacuum or in an atmosphere under reduced pressure to produce a glass article, the inside of a vacuum furnace is preburned while evacuating the furnace at the vitrification temp. of the deposit or above, preferably 1,600-1,700 deg.C before the deposit is heated. Since suspended carbon powder and fine glass particles, residual gas, etc., in the furnace can be removed, a high quality glass article free from foreign matter, bubbles, etc., near the surface can be obtd. |
