Patent ID: 7960301

Claim:
A glass composition which comprises, in mass %, 40 to 70% SiO 2 , 5 to 20% B 2 O 3 , 10 to 25% Al 2 O 3 , 1 to 10% MgO, 0 to 20% CaO, 0 to 20% SrO, 0 to 10% BaO, 0.001 to 0.5% Li 2 O, 0.01 to 0.5% Na 2 O, greater than 0.03% and no greater than 0.5% K 2 O, and greater than 0% and no greater than 1.0% Cl, wherein a total content of Li 2 O, Na 2 O, and K 2 O is in a range of greater than 0.07 mass % and no greater than 1.5 mass %.