A rheological study of a methacrylate homopolymer containing azobenzene side groups and its 70130 copolyiner with methyl methacrylate was perfomed in the linear viscoelastic regime. The creep and oscillatory measurements enabled us to obtain the temperature dependence of the zero shear viscosity eta. The time-temperature superposition principle (TTS) was found to hold over large temperature intervals; in particular no discontinuities were detected at the isotropic-nematic transition in either sample. However, the homopolymer evidenced, a peculiar signature in the shear elastic complex modulus G* (w,T) at a temperature T, in the nematic phase. This was attributed to a conformational transition driven by the nematic order.