The polarization induced by thermopoling the alternating vinylidene cyanide/vinyl acetate copolymer has been studied by the thermal pulse technique. The mean polarization over the thickness and its spatial profile were determined as functions of the poling variables: electric field, time, and temperature. Additionally, the thermal stability of the polarization was studied between ambient temperature and the glass‐transition temperature of 175 °C. The mean polarization was found to be proportional to the poling field up to the maximum field used of 42 MV/m and to be very stable up to 150 °C. The polarization profiles obtained after poling were found to be highly inhomogeneous, especially for short poling times, indicating positive charge injection from the positive electrode during poling. The polarization distribution continues to evolve after the mean polarization has reached a steady state indicating separate time scales for space‐charge migration and dipole reorientation. ©1996 American Institute of Physics.