On the dynamics of the cholestane spin probe in a nematic azobenzene side group oligomer

ESR studies were carried out on the rotational dynamics of the cholestane spin probe dissolved in a nematic methacrylate oligomer containing azobenzene side groups from well above T-NI to below T-g. Only one molecular site was detected in contrast to analogous high molar mass samples, for which distributions of molecular sites were found depending on their thermal histories. The probe dynamics was coupled to that of either the methacrylate main chain or the azobenzene side groups in different temperature regions.