US Patent 7475568 Method of fining glass

A method of forming an oxide glass including heating a glass melt having a β—OH concentration of at least about 0.35 in a vessel comprising a metal selected from the group consisting of platinum, molybdenum, palladium, rhodium, and alloys thereof, there being an interface present between the vessel and the glass, and controlling a partial pressure of hydrogen in an atmosphere in contact with an outside surface of the vessel in an amount such that hydrogen permeation blisters form in a region of the glass adjacent the glass-vessel interface.