Dynamical processes effective on the nanometer length scale are of interest in polymeric systems due to their importance on the structural properties of the materials. In this study, a nm scale molecular probe is dissolved in a polymeric liquid crystal and its reorientation is studied by non-linear Electron Spin Resonance spectroscopy. Different dynamic behaviours as a function of the temperature are observed. Moreover it is found that the rotational motion of the molecular probe is sensitive to the different conformations of the polymer chain, which strongly depend on the thermal history of the material.