The dynamics of the cholestane spin probe dissolved in a nematic azobenzene copolymer was studied by ESR following a suitable thermal procedure. Heterogeneities in the dynamics of the guest molecule resulted to occur only in the high temperature region, slightly above the nematic-isotropic transition temperature. A temperature region above the glass transition was signalled, in which stable optical writing could be obtained. Optical birefringence and topological writing experiments were carried out on polymer films at the macroscopic and nanometer length-scales, respectively. SNOM analysis showed a very homogenous substrate that could be suitable for optical nanowriting.