Profile of the electric field induced in the bulk of thermally poled glass samples

Summary form only given. A second order susceptibility /spl chi/(2) due to the coupling of the third order glass susceptibility /spl chi/(3) with a DC built-in electric field E/sub ind/ has been induced in different thermally poled glasses. Here, for the first time, using a technique based on electric field induced second harmonic (EFISH), we measure the profile of the induced static electric field E in the bulk of the sample during and after the poling. For various temperatures, we monitor the temporal evolution of the electric field in the sample in the range 200/spl deg/C-360/spl deg/C. This process is found to be thermally activated, the measured activation energy are E/sub a/(silica) = 120 /spl plusmn/ 10 kJ/mol /spl sime/ E/sub a/(Na/sup +/) in fused silica and E/sub a/(SF57) = 80 /spl plusmn/ 10 kJ/mol in lead silica.