DRYING AGENT AND IMPROVED PROCESS FOR DRYING SOOT PREFORMS

摘要

The disclosed invention relates to the use of a specific drying agent in a process for drying glass soot preforms. The drying agent includes at least one halide and at least one reducing agent. Preferably, the reducing agent includes a compound that will react with an oxygen by-product of the reaction of the halide and water, or the reaction of the halide and an impurity in the preform. The method includes disposing the soot preform in a furnace, charging the furnace with the drying agent of halide and reducing agent and supplying heat to the furnace. Suitable drying agents for use in the process disclosed include a mixture of Cl2 and CO; a mixture of Cl2, CO and CO2; and POCl3: the latter being an example where the halide and reducing agent are embodied by a single compound.