PRODUCTION OF GLASS ARTICLE

摘要

PURPOSE:To obtain a glass rod or glass pipe free from bend, by depositing glass soot on surface of a column or cylinder of high-purity glass and clarifying the deposited glass soot under specific condition. CONSTITUTION:Glass soot is deposited on a surface of a first column or cylinder of a high-purity glass and is clarified in a high-temperature furnace to obtain the second column or cylinder. The heat-treatment is carried out under a condition to give a shrinkage of deposited glass soot of <=15% within a temperature range to give a glass viscosity of <=10<16> poise and >=10<9> poise. The heat- treatment is preferably carried out by using a soaking pit as the high- temperature furnace and raising the temperature of the furnace at a rate of >=2 deg.C/min on an average between a temperature range to give a glass viscosity of <=10<16> poise and >=10<9> poise (between standby temperature and clarification temperature).