Patent ID: 7297646

Claim:
A method for making an article comprising glass, the method comprising: providing glass particles comprising glass, the glass comprising at least 70 percent by weight of (i) at least one of Nb 2 O 5 or Ta 2 O 5 and (ii) at least two of (a) Al 2 O 3 , (b) REO, or (c) at least one of ZrO 2 or HfO 2 , and the glass containing not more than 30 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 , with the proviso that the glass does not comprise 35.73 percent by weight Al 2 O 3 , 42.17 percent by weight La 2 O 3 , 17.1 percent by weight ZrO 2 , and 5 percent by weight of one of Nb 2 O 5 or Ta 2 O 5 , based on the total weight of the glass, the glass having a T g ; and heating the glass particles above the T g such that the glass particles coalesce to form a shape and provide the article comprising collectively comprising at least 70 percent by weight of (i) at least one of Nb 2 O 5 or Ta 2 O 5 and (ii) at least two of (a) Al 2 O 3 , (b) REO, or (c) at least one of ZrO 2 or HfO 2 , and the glass containing not more than 30 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 , with the proviso that the glass does not comprise 35.73 percent by weight Al 2 O 3 , 42.17 percent by weight La 2 O 3, 17.1 percent by weight ZrO 2 , and 5 percent by weight of one of Nb 2 O 5 or Ta 2 O 5 , based on the total weight of the glass of the article.