Abstract: An optical article exhibits effects attributable to the nonlinear second order polarizability of electromagnetic radiation and comprises a polymer containing within its repeating units polar aligned noncentrosymmetric molecular dipoles having an electron donor moiety linked through a conjugated .pi. bonding system to an electron acceptor moiety to permit oscillation of the molecular dipoles between a ground state exhibiting a first dipole moment and an excited state exhibiting a different dipole moment, characterized in that the molecular dipoles include as an acceptor moiety a vinyl group geminally substituted by two strong electron withdrawing groups, at least one of which is a sulfonyl moiety.