Photoreversible optical nonlinearities of polymeric films containing spiropyran with long alkyl chains

It was demonstrated that the third‐order optical nonlinearity of polymer films could be reversibly controlled by the photochromic conversion and following J‐aggregate formation of spiropyran embedded in an inert polymer matrix. Patterns consisting of areas with high and low third‐order nonlinear optical activities were prepared by imagewise exposure of the photochromic films followed by thermal treatment to form thermally stable J aggregates of photoinduced merocyanine in the exposed area. This system could be useful in developing new unconventional optical devices based on optical nonlinearities, including new types of spatial light modulators.