We have found that the application of light to strontium barium niobate (SBN) during electrical repoling stabilizes the newly formed domains. This stabilization becomes apparent when repoling the crystal back into its original domain direction as a change in the distribution of displacement current as a function of voltage. This appears to be the process underlying the other recent work in the area of optical control of domain structures for quasi‐phase‐matching of nonlinear processes. We present an explanation for this effect in terms of the microdomain structure of SBN. This model should aid in the search for new materials for optical periodic poling. ©1996 American Institute of Physics.