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 investigate the electric field distribution in soda-lime glass samples after application of a dc potential (dc poling). The modifications of near-surface composition resulting from the dc polarization procedure were determined by means of three nuclear techniques for near-surface analysis: Rutherford backscattering spectrometry (RBS), elastic recoil detection analysis (ERD) and nuclear reaction analysis. An alkali-depleted layer is formed near the anode. This depletion layer persists for a long time after the dc poling. The electric field in this region is of the order of the intrinsic dielectric breakdown, and its configuration depends 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 ionized electrons are probably the charge carriers in the alkali-depleted layer.