de Biasing with a pulse train enabled us to follow the process of solid-state anodization of aluminum on silver metaphosphate glass, a silver-ion conductor. Anodization induced formation of a dielectric oxide in which the capacitance (around 10(-7) F/cm(2)) decreased with increasing bias field, caused by an increase in oxide thickness. The oxide formed would not be the genuine alumina but contains phosphorus (and possibly silver).