US Patent 7854144 Method of reducing gaseous inclusions in a glass making process

Feed materials are melted in a first vessel to form a glass melt at a first temperature T1, the glass melt containing at least one fining agent. The molten glass is next cooled to a second temperature T2 less than T1 in a second vessel wherein an oxygen-comprising gas is not actively added (e.g. bubbled) into the melt during the duration of the time the melt is at T2. The molten glass is thereafter heated to a third temperature T3 greater than T1 and subsequently formed into a glass article.