| 摘要 |
PURPOSE:To produce the title transparent glass as the optical fiber base material having an extremely low content of impurities by oxidizing the impurities in the porous glass body obtained from the agglomerate of fine glass particles in an oxygen atmosphere, then dehydrating the body with chlorine, and removing the impurities. CONSTITUTION:The porous glass body 1 consisting of the agglomerate of the fine glass particles consisting essentially of SiO2 is hung by a supporting rod 4 and placed in a furnace core tube 5, an oxygen-contg. gas is supplied from a gas inlet 6 and discharged from an outlet 7 while heating the body by a heater 3, and the metallic impurities such as Fe and Cr contained in the porous glass 1 are transiently oxidized. A chlorinous gas such as Cl2, CCl4, and SOCl2 is introduced into the furnace core tube 5 to remove the water contained in the porous glass body 1, and the oxidized metallic impurities are easily volatilized and removed. An extremely high-purity transparent glass material for an optical fiber can be obtained. |
