Low iron high transmission glass with boron oxide for improved optics, durability and refining, and corresponding method

Abstract

This invention relates to a high transmission low iron glass that includes boron oxide. The boron oxide, added to this low iron glass, has the effect of improving glass refining, homogeneity and quality (lower seed count) through its flux action and improves glass optical parameters of green and clear glass through the change in refractive index and surface tension. Boron oxide lends to broader and weaker absorption band of such transition element(s) as iron which additionally improves the transmittance of low iron clear glass in certain example embodiments of this invention. In certain example embodiments, the addition of boron oxide in certain quantities in advantageous in that it improves the chemical durability of the glass by decreasing the USPX (or USPXIII) value of the glass via suppression of the silica, sodium ions in the glass structure.

1 . Glass comprising: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   Ingredient 
                   wt. % 
                 
                     
                     
                 
                     
                   SiO 2   
                   69-73% 
                 
                     
                   Na 2 O 
                   10-20% 
                 
                     
                   CaO 
                    5-15% 
                 
                     
                   MgO 
                   0-5% 
                 
                     
                   K 2 O 
                   0-2% 
                 
                     
                   total iron (expressed as Fe 2 O 3 ) 
                   0.005 to 0.04%  
                 
                     
                   FeO 
                      0 to 0.0035% 
                 
                     
                   cerium oxide 
                     0 to 0.03% 
                 
                     
                   boron oxide 
                   0.1 to 2.5% 
                 
                     
                   SO 3   
                   0.1 to 0.6% 
                 
                     
                     
                 
             
                
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
       wherein the glass has a glass redox of no greater than 0.12, a USPX value of no greater than 5.8, and a total solar transmission (ISO 9090 1.5 AM, at 3.2 mm reference thickness) of at least 90.8%. 
     
     
         2 . The glass of  claim 1 , wherein the glass comprises: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   total iron (expressed as Fe 2 O 3 ) 
                   0.005 to 0.03% 
                 
                     
                   boron oxide 
                     0.5 to 1.5%. 
                 
                     
                     
                 
             
                
               
               
                
                
                
               
            
           
         
       
     
     
         3 . The glass of  claim 1 , wherein the glass has a total solar (τe) transmission of at least 90.9%. 
     
     
         4 . The glass of  claim 1 , wherein the glass is substantially free or free of each of erbium oxide, nickel oxide, cerium oxide, cobalt oxide, zirconium oxide, zinc oxide, neodymium oxide, and selenium. 
     
     
         5 . The glass of  claim 1 , wherein the glass is substantially free or free of erbium oxide, cerium oxide, zirconium oxide, zinc oxide, and nickel oxide. 
     
     
         6 . The glass of  claim 1 , wherein the glass has a positive b* color value. 
     
     
         7 . The glass of  claim 1 , wherein the glass has a glass redox value (FeO/Fe 2 O 3 ) no greater than 0.10. 
     
     
         8 . The glass of  claim 1 , wherein the glass comprises from 0 to 0.0020% FeO. 
     
     
         9 . The glass of  claim 1 , wherein the glass substrate is substantially free of four or more of erbium oxide, nickel oxide, cobalt oxide, neodymium oxide, chromium oxide, cerium oxide and selenium. 
     
     
         10 . The glass of  claim 1 , wherein the glass substrate is substantially free of seven or more of erbium oxide, nickel oxide, cerium oxide, cobalt oxide, neodymium oxide, zirconium oxide, zinc oxide and selenium. 
     
     
         11 . The glass of  claim 1 , wherein the glass is substantially free of erbium oxide, cerium oxide, zirconium oxide, zinc oxide and nickel oxide. 
     
     
         12 . The glass of  claim 1 , wherein the glass has a transmissive a* color value of −0.5 to +0.5 and a transmissive b* color value of from +0.1 to +1.0.