We investigated electrical conduction phenomena, which occurred during high electric field electrode poling of side chain &khgr;(2)polymers. Electric current and second harmonic intensity were measured simultaneously in poling experiments performed on samples with and without an additional inorganic poly–methyl–siloxane layer. Current densities appeared to be limited by a Schottky‐type potential barrier at the electrode/insulator interface. The field dependence of the current density was found to beSchottkychargeemissionfor medium field strengths (EPOL≤100 V/&mgr;m) whereas it was dominated byFowler–Nordheimtunnelingat higher poling fields. In the presence of the siloxane layer, a significant suppression of tunneling current was observed. This leads to a reduced probability of singular dielectric breakdown events and shifts the limit of avalanche breakdown to higher internal effective poling field strengths. ©1996 American Institute of Physics.