Origin of electrooptical sensitivity of glasses

A niobium-lithium-silicate glass demonstrating a record Kerr coefficient (266•10 -16 m/V 2 ) has been formed, and transparent glass-ceramics demonstrating Kerr coefficients exceeding 6000•10 -16 m/V 2 has been elaborated. A conception of the origin of electrooptical sensitivity of glasses is developed. It supposes that the fluctuation microinhomogeneities peculiar to as-prepared glasses are the regions with exact crystalline symmetry, and that just those regions are the pre-nuclei of the crystallites, which form in glass-ceramics in heat treatment. Having the composition and the symmetry of electrooptical ferroelectric crystal, these regions appear to condition high Kerr sensitivities of both the glasses and the glass-ceramics formed from these glasses.