In this paper we present a study of photoinduced effects, including molecular relaxation in a side chain liquid crystalline polymer. In particular, we have studied relaxation phenomena using Ellipsometry and Photoinduced Birefringence in pump-probe experiments, which were carried out as a function of temperature, optical pump intensity and sample preparation and history. Two specific areas were investigated in detail: the frustration effect of the trans-cis photoisomerization transition on the nematic phase, and hence the photoinduced isothermal transition from perturbed nematic to a totally frustrated (isotropic) phase; and the approach of the glass transition, in such a fragile polymeric glass as the one we studied.