PROCESS FOR PREVENTING COLORATION OF SILICA GLASS PRODUCED BY SOL-GEL METHOD

摘要

PURPOSE: A process for preventing coloration of silica glass obtained by sol-gel method is provided to execute smooth exhausting flow to protect the coloration state of the silica glass by containing low-temperature thermal treatment procedure. CONSTITUTION: The process comprises measuring exhaust gas pressure parameters such as exhaust gas line size or supplying gas flow rate; setting up reference level of subject reference exhaust gas pressure according to the parameters measured from the first step; and varying positive/negative pressures to add or reduce the exhaust gas pressure in terms of the reference level depending on variation of the exhaust gas pressure parameters. The reference pressure is set up equal to the atmosphere pressure level and the step for varying positive/negative pressures is achieved by controlling fluid level of a fluid storage tank connected to the exhaust gas line.