POTASSIUM FREE ZINC SILICATE GLASSES FOR ION-EXCHANGE PROCESSES

摘要

A fluorinated zinc−silicate glass having a composition, expressed in molar percent, of essentially from about 49 to about 69 % SiO2, from about 2 % to about 30 % ZnO, from about 3.9 to about 18 % Al2O3, from about 10 % to about 16.7 % Na2O, from about 0 % to about 13 % B2O3, from about 0 % to about 0.8 % MgO, from about 0 % to about 0.7 % BaO, from about 0 % to about 3 % Zr02, from about 0 % to about 6.7 % CaO, from about 0 % to about 0.11 % As2O3, from about 0 % to about 0.07 % Sb2O3, from about 0 % to about 3 % NaF and from about 0 % to about 3.9 % AlF3. The glass can be prepared in optical quality slabs, is chemically durable in water, NaNO3 salt melts and boiling NaOH, and has a refractive index close to that of the optical fiber to reduce coupling losses. The glass includes Na as a single alkali ion species exchangeable for silver in an ion−exchange process that provides a sufficient index change for waveguiding.