Methods for manufacturing glass articles

Abstract

Methods of producing a glass article include melting a first glass composition and feeding a second glass composition into the melter. Both glass compositions include the same combination of components but at least one component has a concentration that is different in each. At least three glass articles may be drawn from the melter, including: a first glass article formed from the first glass composition; at least one intermediate glass article composed of neither the first nor the second glass composition; and a final glass article not composed of the first glass composition. The concentration of the at least one component in the intermediate glass article may be between the concentration in the first and second glass compositions. The first glass article and final glass article may have differing values for certain properties, and the intermediate glass article may have an intermediate set of values for the same properties.

What is claimed is: 
     
         1 . A glass article formed from a glass composition comprising:
 greater than or equal to 45 wt. % and less than or equal to 55 wt. % SiO 2 ;   greater than or equal to 20 wt. % and less than or equal to 27 wt. % Al 2 O 3 ;   greater than or equal to 8 wt. % and less than or equal to 10 wt. % B 2 O 3 ;   greater than or equal to 0 wt. % and less than or equal to 8 wt. % Na 2 O;   greater than or equal to 0 wt. % and less than or equal to 6 wt. % MgO;   greater than or equal to 7 wt. % and less than or equal to 9 wt. % CaO;   greater than or equal to 0 wt. % and less than or equal to 0.7 wt. % Sb 2 O 3 ; and   greater than 0 wt. % and less than or equal to 1.5 wt. % AlF 3 .   
     
     
         2 . The glass article of  claim 1 , wherein the glass composition comprises greater than 0.5 wt. % and less than or equal to 1.5 wt. % AlF 3 . 
     
     
         3 . The glass article of  claim 1 , wherein the glass composition comprises greater than or equal to 22 wt. % and less than or equal to 27 wt. % Al 2 O 3 . 
     
     
         4 . The glass article of  claim 1 , wherein the glass composition comprises greater than or equal to 0 wt. % and less than or equal to 10 wt. % K 2 O. 
     
     
         5 . The glass article of  claim 4 , wherein the glass composition comprises greater than or equal to 0 wt. % and less than or equal to 7 wt. % K 2 O. 
     
     
         6 . The glass article of  claim 1 , wherein the glass composition comprises at least one alkaline earth oxide in an amount greater than or equal to 1 wt. % and less than or equal to 22 wt. %. 
     
     
         7 . The glass article of  claim 6 , wherein the glass composition comprises at least one alkaline earth oxide in an amount greater than or equal to 9 wt. % and less than or equal to 22 wt. %. 
     
     
         8 . The glass article of  claim 1 , wherein the glass composition comprises greater than or equal to 0 wt. % and less than or equal to 5 wt. % Na 2 O. 
     
     
         9 . The glass article of  claim 1 , wherein the glass composition comprises greater than or equal to 1 wt. % and less than or equal to 8 wt. % Na 2 O. 
     
     
         10 . The glass article of  claim 1 , wherein the glass composition comprises greater than or equal to 2 wt. % and less than or equal to 7.5 wt. % Li 2 O. 
     
     
         11 . The glass article of  claim 1 , wherein the glass composition comprises greater than or equal to 1 wt. % and less than or equal to 3 wt. % MgO. 
     
     
         12 . The glass article of  claim 1 , wherein the glass composition comprises greater than or equal to 0.5 wt. % and less than or equal to 3 wt. % SrO. 
     
     
         13 . The glass article of  claim 1 , wherein the glass composition comprises greater than or equal to 0.25 wt. % and less than or equal to 0.50 wt. % SnO 2 . 
     
     
         14 . The glass article of  claim 1 , wherein the glass composition comprises less than or equal to 15 wt. % ZnO. 
     
     
         15 . The glass article of  claim 14 , wherein the glass composition comprises less than or equal to 15 wt. % ZrO 2 . 
     
     
         16 . The glass article of  claim 1 , wherein the glass article has a Young's modulus of greater than or equal to 65 GPa. 
     
     
         17 . The glass article of  claim 16 , wherein the glass article has a Young's modulus of greater than or equal to 65 GPa and less than or equal to 100 GPa. 
     
     
         18 . The glass article of  claim 1  wherein the glass article has a 200 Poise temperature of less than 1500° C. 
     
     
         19 . The glass article of  claim 1 , wherein a CTE of the glass article is 40 to 70×10 −7 /° C. over the range from 20° C. to 260° C.