Influence of Ag/sup +/-Na/sup +/ ion-exchange equilibrium on waveguide index profiles

Abstract
The Ag/sup +/-Na/sup +/ ion-exchange process in a soda-lime silicate glass was studied at 330 degrees as a function of composition of AgNO/sub 3/-NaNO/sub 3/ melt, mixing condition, and exchange time. The concentration profile of silver in glass was measured by atomic absorption spectroscopy and SEM technique. The surface index change and the index profile were determined from mode index measurement. Ion-exchange was modeled by an ion-diffusion limited process in the glass with an equilibrium chemical reaction at the melt-glass interface. A large value of 75 for the equilibrium constant at low-silver melt concentrations (