PROCESS FOR PRODUCING SHEET GLASS BY THE OVERFLOW DOWNDRAW FUSION PROCESS

摘要

Methods are provided for controlling the formation of defects in sheet glass produced by the overflow downdraw fusion process which employs a zircon isopipe. The methods comprise controlling the temperature profile of the glass as it passes over the isopipe so as to minimize both the amount of zirconia which diffuses into the glass at the top of the isopipe and the amount of zircon which comes out of solution at the bottom of the isopipe.