Nonsinusoidal and asymmetric surface relief (SR) gratings, formed in azobenzene-containing polymeric films by elliptical polarization holographic recordings, were theoretically characterized. The amplitude of SR deformation was formulated on the basis of the optical-field gradient force model and calculated using the electric field of the interference light and the dielectric polarization of the recorded film. The observed SR gratings with asymmetric structures were well explained by considering the Weigert effect of azobenzene molecules. This observation suggests that SR deformation on the azopolymer film originating from mass transportation is affected by the distribution of optical anisotropy induced by the reorientation of the azobenzene molecules.