PROCESS FOR PRODUCING GLASS

摘要

This invention provides a production process of glass that can shorten the time necessary for the addition of a refractive index control material such as fluorine to a glass fine particle deposited product. This process comprises the steps of (1) placing a glass fine particle deposited product in a vessel, (2) supplying an addition gas containing a refractive index control material into the vessel and evacuating gas within the vessel to add the refractive index control material to the glass fine particle deposited product, and (3) heating the glass fine particle deposited product for clearing. In the step in which a final setting concentration of the refractive index control material in the addition gas is determined from a target glass refractive index and the refractive index control material is added, an addition gas containing a refractive index control material having a higher setting concentration than the final setting concentration is supplied to the vessel, and an addition gas containing a refractive index control material having a final setting concentration is then supplied into the vessel to add the refractive index control material to the glass fine particle deposited product.