We demonstrate a method of permanent optical recording of digital data which exploits a fast photoisomerization of nonlinear molecules, followed by a slow permanent alignment within a polymer. Write and erase cycles are initiated by rapidly photoisomerizing azobenzene molecules into an intermediate state with a larger mobility. The molecules align or randomly orient within the polymer depending on the presence or absence of an electric field. During orientation, relaxation to a stable isomer occurs and the alignment becomes permanent. The recorded information can then be nondestructively read by second‐harmonic generation. Nanosecond optical exposures were used, demonstrating that extremely fast recording rates are possible. ©1995 American Institute of Physics.