ELECTRIC-FIELD DISTRIBUTION AND NEAR-SURFACE MODIFICATIONS IN SODA LIME GLASS SUBMITTED TO A DC POTENTIAL

The laser-induced pressure pulse method (LIPP) is employed to investig ate the electric field distribution in soda-lime glass samples after a pplication of a dc potential (dc poling). The modifications of near-su rface composition resulting from the dc polarization procedure were de termined by means of three nuclear techniques for near-surface analysi s: Rutherford backscattering spectrometry (RBS), elastic recoil detect ion analysis (ERD) and nuclear reaction analysis. An alkali-depleted l ayer is formed near the anode. This depletion layer persists for a lon g time after the dc poling. The electric field in this region is of th e order of the intrinsic dielectric breakdown, and its configuration d epends on the penetration, or not, of hydrogen. Based on these results , the conduction mechanism in the alkali-depleted layer is discussed. It is suggested that when hydrogen blocking electrodes are used ionize d electrons are probably the charge carriers in the alkali-depleted la yer.