Layer separation of He+-ion implanted relaxor ferroelectric films (0.955)[Pb(Zn1/3Nb2/3)O3]–(0.045)[PbTiO3] (0.955PZN-0.045PT) has recently been reported in the literature.[1,2] Here we report on optical and X-ray diffraction analysis of the implanted material prior to separation. The formation of optical waveguides as a result of He+-ion implantation enables us to probe the sacrificial layer. A large refractive index contrast is observed between this layer and the film. Significant tetragonal distortions are also seen in the waveguide region (“the film”). Rapid thermal processing (RTP) significantly changes the peak position of the index contrast profile, possibly indicating a large redistribution of stress by He evolution in the sacrificial layer. A commensurate reduction in tetragonal distortion and local strain distribution in the waveguide region to values close to those observed before implantation is measured by triple crystal high resolution X-ray diffraction.