Porous glass base material sintering method

Abstract

It is an objective of the present invention to provide a method for sintering a porous glass base material that can experience an earthquake or large vibration without the base material falling or decreasing in quality when performing sintering, dehydration, and transparent vitrification on the porous glass base material. Provided is a method of sintering a porous glass base material including sintering by lowering the porous glass base material vertically through a furnace from above while rotating the porous glass base material, the method comprising changing rotational speed of the porous glass base material during the sintering.

Dependencies are inferred from the claim text.