Ostroverkhova Oksana, He Meng, Twieg Robert J, Moerner W E
Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
Chemphyschem. 2003 Jul 14;4(7):732-44. doi: 10.1002/cphc.200200633.
We present a detailed temperature-dependence study of dielectric, birefringent, conductive, and photorefractive (PR) properties of high-performance low-molecular weight organic glasses that contain 2-dicyanomethylene-3-cyano-2,5-dihydrofuran (DCDHF) derivatives. DCDHF organic glasses sensitized with C60 exhibit high two-beam coupling gain coefficients in the red-wavelength region. However, in the best performing DCDHF glasses at room temperature the PR dynamics are limited by slow molecular reorientation in the electric field. While orientational and, therefore, PR speed can be significantly improved by increasing the temperature above the glass-transition temperature of the material, the steady-state performance may worsen. Comprehensive study of the temperature dependence of various processes, which contribute to the PR effect in DCDHF glasses, clarifies the limiting factors and allows for optimization of the overall PR performance.
我们对含有2-二氰基亚甲基-3-氰基-2,5-二氢呋喃（DCDHF）衍生物的高性能低分子量有机玻璃的介电、双折射、导电和光折变（PR）特性进行了详细的温度依赖性研究。用C60敏化的DCDHF有机玻璃在红色波长区域表现出高的双光束耦合增益系数。然而，在室温下性能最佳的DCDHF玻璃中，PR动力学受到电场中缓慢分子重取向的限制。虽然通过将温度提高到材料的玻璃化转变温度以上可以显著提高取向性，从而提高PR速度，但稳态性能可能会变差。对各种过程的温度依赖性进行综合研究，这些过程对DCDHF玻璃中的PR效应有贡献，阐明了限制因素，并有助于优化整体PR性能。
