Patent ID: 8536787

Claim:
A glass composition that is P 2 O 5 —ZnO—SnO—Al 2 O 3 -based and does not contain Sb, the glass composition comprising, in oxide-based mol %: (a) at least 30% and at most 50% P 2 O 5 , (b) at least 10% and at most 50% ZnO, (c) at least 0.1% and at most 10% Al 2 O 3 , (d) at least 0% and at most 50% Li 2 O, (e) at least 0% and at most 50% Na 2 O, (f) at least 0% and at most 50% K 2 O, (g) at least 0% and at most 20% MgO, (h) at least 0% and at most 20% CaO, (i) at least 0% and at most 20% SrO, (j) at least 0% and at most 20% BaO, (k) at least 0% and at most 20% SnO, and (l) at least 0.2% and at most 5% B 2 O 3 , substantially not comprising ZrO 2 and Ag 2 O, and (a)/(b), the ratio of (a) and (b), being at least 0.2 and at most 2.0.