Pb(Mg 1/3 Nb 2/3 ) 0.90 Ti 0.10 O 3 (10PMNT) polycrystalline thin films were deposited on TiN/Si substrates by laser ablation using 248 nm wavelength, 30 ns duration pulses from a KrF excimer laser with a 10 Hz repetition rate and a fluence of 2 J cm −2 . The samples were deposited at 250 • C and post-annealed at temperatures between 500 and 600 • C. The presence of a dominant 10PMNT perovskite phase was confirmed by x-ray diffraction analysis as well as a secondary pyrochlore phase whose relative abundance increased with the annealing temperature. The electrical properties and the influence of the annealing temperature on the dielectric properties of the 10PMNT thin films were characterized through P-E hysteresis loop studies. Electrical and optical stress measurements were used to evaluate the long-term performance of the 10PMNT/TiN/Si heterostructure. We demonstrate that rejuvenation of electrically fatigued PMNT films is possible by applying optical stress via UV light; however, it can also be limited by other factors. We suggest that polarization fatigue in PMNT is essentially a dynamic competition between domain wall pinning due to electronic charge trapping and trapped charges like oxygen vacancies at the interface and UV/electric field-assisted unpinning of the domain wall.