| 摘要 |
A glass-ceramic which is substantially and desirably totally transparent, and which contains a willemite predominant crystal phase within the ternary Mg2SiO4-Zn2SiO4-Li4SiO4 system. The glass-ceramic is formed from precursor glasses having the following compositions, in weight percent on an oxide basis, of 25-60 SiO2, 4-20 Al2O3, 20-55 ZnO, 0-12 MgO, 0-18 K2O, 0-12 Na2O, 0-30 GeO2, with the condition that SIGMA K2O+ Na2O >/= 5. The glass-ceramic may be doped with up to 1 wt. % Cr2O3 to impart optical activity thereto. |
