Grey tracks produced in KTiOPO4(KTP) by applying a dc electric field have been studied through optical absorption, Raman scattering, and synchrotron x‐ray topography. A study of the optical absorption and Raman scattering from the grey‐tracked region suggests that their formation is accompanied by changes in the electronic levels of Ti4+. There is no evidence for a major structural change or disorder in the grey‐tracked region. However, the x‐ray topographs do indicate the presence of a remnant strain in the lattice, which might contribute to the observed changes in the Raman intensities. ©1995 American Institute of Physics.