The influence of cooling process on gas bubbles in high-purity quartz glass

This paper investigates the gas bubble evolution in the cooling process of the fabrication of electrically melted high-purity quartz glass. The experiment proves that the cooling rate regulates the quantity and size of gas bubbles in quartz glass. Using an appropriate cooling rate can effectively reduce the number of gas bubbles and decrease the gas bubble size in quartz glass, which is proposed to stem from the dissolution of SiO gas and CO gas into glass substrate. As the temperature decreases, the solubility of the gas in the glass increases, while the slow cooling process allows the gas in the gas bubbles have more sufficient time to dissolve. The dissolution of gas in the gas bubbles further reduces the size of gas bubbles and macroscopically, the number of gas bubbles within the visible size range of glass decreases. In addition, a two-stage cooling process was demonstrated to be able to further reduce the gas bubble volume in quartz glass, which is combined with a rapid cooling in the higher temperature range to reduce the generation of gas bubbles and a slow cooling in the lower temperature range to promote the dissolution of gas bubbles. The research on the gas bubble evolution in the cooling process in this paper is of great significance and value for the preparation of high-purity quartz glass.