| 摘要 |
PURPOSE:To make a base material thoroughly transparent while preventing the surface deterioration by feeding a gaseous compound contg. chlorine along the inner peripheral wall of a heating furnace to carry out the complete thermal decomposition of the compound, and using the resulting gaseous chlorine when a soot rod is made transparent by dehydration. CONSTITUTION:A gaseous compound contg. chlorine is fed along the inner peripheral wall of a heated heating furnace to carry out the complete thermal decomposition of the compound, and the resulting gaseous chlorine is mixed with gaseous helium. A soot rod obtd. by a vapor phase chemical vapor deposition method is introduced into the mixed gaseous atmosphere in the heating furnace, where the rod is brought into contact with the gaseous chlorine, and it is made transparent by dehydration. By this method the base material is made thoroughly transparent while preventing the surface deterioration. |
