It has been observed in the literature that when the DC poling voltage is removed at the end of the poling process in glass in a so called de-poling experiment, the small signal AC impedance as measured by impedance spectroscopy increases immediately. It is shown that this effect can be explained if the DC voltage causes nonlinear ionic conduction to occur in the poled layer. The DC field changes the barrier height over which ions have to jump from one site to another and this also effects the AC resistance; by removing the DC field the original barrier height is restored thus increasing the AC resistance. Analysis of experimental data using poled soda-lime glass supports this interpretation.