Dielectric spectroscopy and molecular dynamics of epoxy oligomers with covalently bonded nonlinear optical chromophores

Abstract

Dielectric behavior of two epoxy-based oligomers with covalently attached 4-amino-4′-nitroazobenzene NLO chromophore fragments is studied. Four processes of relaxation of dipole polarization, γ-, β-, β1-, and α-processes are identified by the method of dielectric spectroscopy. Monte-Carlo conformational analysis and molecular dynamics of dimeric chain fragments of these polymers is performed and mobilities of specific chain fragments are estimated. Molecular mechanisms for the γ-, β-, and β1-processes, occurring in the glassy state, are suggested on the basis of a comparison of the dielectric spectroscopy and molecular modeling data.