Patent ID: 7175786

Claim:
A method for making glass, the method comprising: feeding at least Al 2 O 3 source and particulate SiO 2 source into one of a flame or a plasma to provide a melt, wherein the particulate SiO 2 has an average particle size in a range from 5 nm to 50 micrometers, and wherein at least 90 percent by weight particulate SiO 2 source have a particle size in a range from 5 nm to 50 micrometers; and cooling the melt to provide a glass comprising at least 60 percent by weight Al 2 O 3 and SiO 2 in a range from 0.5 to 10 percent by weight, and not more than 10 percent by weight collectively As 2 O 3 , B 2 O 3 , GeO 2 , P 2 O 5 , SiO 2 , TeO 2 , and V 2 O 5 , based on the total weight of the glass.