This paper presents a study of two copolymers, maleic anhydride and methylmethacrilate/maleic anhydride and vinyl benzyl chloride, functionalised with polar chromophoric groups such as 2,4 dinitroaniline. Thin films have been prepared by vacuum evaporation and spin coating methods on silicon and glass substrates. UV-VIS, FTIR, XRD and Photoluminescence Spectroscopy have been used to comparatively investigate the effect of the preparation method on the properties of the thin films obtained with functionalized copolymer. SEM has evidenced differences in the morphologies of the layers suggesting a degradation of the polymeric chain during the evaporation process to fragments that conserve unchanged the chromophoric group. This explains the presence of two types of non-linear phenomena, the second harmonic emission and two-photon luminescence emissions for both vacuum evaporated and spin coated films.