Second order non-linear optical interpenetrating polymer networks based on polyurethane or poly(methyl methacrylate) and epoxy polymer

Two interpenetrating polymer networks (IPNs), (one pseudo-IPN consisting of a linear polyurethane/epoxy-based polymer network and one full-IPN consisting of a poly(methyl methacrylate)/epoxy-based polymer network) have been synthesized and characterized. Both IPNs showed only one T_g; hence a homogeneous phase morphology is suggested. The second-order non-linear optical coefficients (d₃₃) of the pseudo-IPN and the full-IPN were measured and found to be 2.78 × 10⁻⁷ esu and 1.86 × 10⁷ esu, respectively. The study of temporal stability at room temperature and elevated temperature (120 °C) indicates that the full-IPN is more efficient at improving the orientational stability of the non-linear optical chromophores than the pseudo-IPN, because of the permanent entanglements of the two component networks in the full-IPN. © 1999 Society of Chemical Industry