Quantitative, rational predictions of the long-term, temporal decay properties of second-order nonlinear optical polymers from the analysis of relaxation dynamics. Dhinojwala, Ali; Hooker, Jacob C.; Torkelson, John M. Dep. of Chemical Engineering and Dep. of Materials Science & Eng., Northwestern Univ., Evanston, IL, USA. ACS Symp. Ser. (1995), 601(Polymers for Second-Order Nonlinear Optics), 318-32. CODEN: ACSMC8 ISSN: 0097-6156. Journal written in English. CAN 123:200039 AN 1995:791927 CAPLUS

An accelerated method of testing has been developed which allows quant., rational prediction of the temporal decay properties of second-order nonlinear optical (NLO) polymers under conditions of technol. interest but which are exptl. inaccessible. This is accomplished by using a novel delay-trigger technique to monitor the reorientation of NLO chromophores doped and labeled in amorphous polymers over 12 decades in time (10-6 to 106 sec). By fitting the time-dependent orientational component of the second-order macroscopic susceptibility, c(2), to the Kohlrausch-Williams-Watts expression, an av. orientation relaxation time, < t >, is detd. in both the glassy and rubbery states. Reorientation dynamics of Disperse Red 1 (DR1) above Tg, is coupled to the a-relaxation of polystyrene (PS) and poly(iso-Bu methacrylate) (PIBMA). The temporal stability of c(2) can be enhanced by phys. aging the sample or by covalent attachment of the chromophore. However, increases in <t> at a given temp. for the methacrylate-based copolymers with increasing functionalization is due to the increasing Tg of the copolymer with greater chromophore content. Finally, the issue of poling method and conditions are considered in terms of correctly interpreting the temporal behavior of SHG properties in NLO polymers.