| 摘要 |
<p>PURPOSE:To adjust easily the bulk density and obtain the titled large-sized base material stably in high yield, by flowing an Si hydride as a glass raw material having a greater heat of reaction than the glass raw material to be flowed in the central burner into the second burner and thereafter from the center. CONSTITUTION:A gas, e.g. SiCl4, GeCl4, H2, O2 or Ar, is made to flow from a burner 11 forming the central part in producing a porous glass base material, and an Si hydride compound having a greater heat of reaction than SiCl4, e.g. SiHCl3, SiH2Cl2 or SiH4, H2, O2 or Ar, is made to flow from the second burner 12 and burned. the above-mentioned glass raw material is subjected to flame hydrolysis, and the formed granular glass is deposited on a rotating starting material and grown in the rotational direction to afford the titled porous base material.</p> |
