US 7,538,053 B2
Composition of glass for the production of glazing
Laurent Teyssedre, Paris (France); and Dominique Sachot, Ozoire la Ferriere (France)
Assigned to Saint-Gobain Glass France, Courbevoie (France)
Appl. No. 10/508,005
PCT Filed Mar. 19, 2003, PCT No. PCT/FR03/00868
§ 371(c)(1), (2), (4) Date Feb. 01, 2005,
PCT Pub. No. WO03/080527, PCT Pub. Date Oct. 02, 2003.
Claims priority of application No. 02 03873 (FR), filed on Mar. 27, 2002.
Prior Publication US 2006/0234849 A1, Oct. 19, 2006
Int. Cl. C03C 3/087 (2006.01)
U.S. Cl. 501—70  [501/71] 16 Claims
 
1. A glass composition comprising, in weight percent:
   
  SiO2 64-75%
  Al2O3 0-5%
  B2O3 0-5%
  CaO  5-15%
  MgO 0-5%
  Na2O 10-18%
  K2O 0-5%
   
and coloring agents which comprises, in weight percent:
   
  Fe2O3 (total iron) 0.2-0.45%
  Se  2-8 ppm
  CoO 0-20 ppm
  NiO 0-80 ppm
   
wherein said coloring agents satisfy the following relationship:
0.7<(200×NiO)+(5000×Se)+(6×Fe3+)/(875×CoO)+(24×Fe2+)<1.6 wherein the NiO, Se, Fe3+, CoO and Fe2+ contents are expressed in ppm, Fe3+ is the content of ferric iron expressed in the form of Fe2O3 and Fe2+ is the content of ferrous iron expressed in the form of FeO,
wherein the composition has an excitation purity of less than or equal to 2%, a redox from 0.28 to 0.5, an overall light transmission under illuminant A (TLA) greater than 65% and a selectivity (SE) of greater than 1.25, when measured for a thickness of 3.85 mm.