Relaxation of the Second Order Optical Susceptibility in Side-Chain and Main-Chain Nonlinear Optical Polymers

9318948用于光子应用的海登非线性光学材料将使用一种新的方法来测量客体、侧链和主链非线性光学聚合物中非线性光学系数在不同温度下的衰减随压力的变化。通过对客体和侧链形式的巴比妥酸衍生物的系统研究，将检验客体-宿主体系中二阶非线性光学极化率的松弛与单个重复单元的运动有关的假设。最后，这项研究将通过测量自由体积的可压缩性和位移因子的压力依赖性来扩展对玻璃材料中局部聚合物动力学的理解。由位移因子的压力依赖关系确定的活化体积将与Adam和Gibbs的构型熵理论中假设的“重组单元”的大小有关。%通过研究NLO材料的松弛随压力的变化，将确定与NLO部分重定向有关的体积。这将使设计者能够为高速光调制器、波导谐波发生器和光开关等光子设备开发更高稳定性的下一代材料。

9318948 Hayden Nonlinear optical (NLO) materials for photonic applications will be studied using a new method to measure the pressure dependence of the decay of NLO coefficients at various temperatures in guest- host, side-chain, and main-chain NLO polymers by in-situ second harmonic generation. By performing a systematic study of a barbituric acid derivative in a guest-host and side-chain form, the hypothesis that the relaxation of the second order NLO susceptibility in a guest-host system is associated with the motion of a single repeat unit will be tested. Finally, this study will extend the understanding of local polymer dynamics in glassy materials by measuring the compressibility of the free volume and pressure dependence of the shift factor. The activation volume determined from the pressure dependence of the shift factor will be related to the size of the "reorganizing units" postulated in the configurational entropy theory of Adam and Gibbs. %%% By studying the relaxation of NLO materials as a function of pressure, the volume associated with the reorientation of the NLO moiety will be determined. This will allow designers to develop higher stability next generation materials for photonic devices such as high-speed optical modulators, waveguide harmonic generators and optical switches.