有机/无机薄膜凝胶动态过程的实时光学二次谐波产生研究

采用实时光学二次谐波产生(SHG)测量方法，以两亲性分子半花菁为掺杂探针分子，对溶胶-凝胶技术制备的玻璃薄膜的凝胶干燥的动态过程进行了研究.结合紫外—可见吸收光谱的测量，发现：因两亲性分子在膜中的自取向性可诱导出二阶光学非线性，溶胶-凝胶技术制备的有机/无机复合膜的凝胶干燥过程可通过薄膜SHG强度的变化半定量地反映.凝胶干燥收缩导致有序掺杂分子数减少，膜片的光学非线性减弱.该过程随薄膜处理温度的升高而急剧缩短；另外，有机分子在膜中的聚集程度随膜片处理温度的增加而很快减少. 关键词：

SECOND-ORDER OPTICAL NONLINEARITY INVESTIGA-TION ON THE GELLING PROCESS OF ORGANIC-DOPED SILICA FILM

The gelling process of organic-doped silica film fabricated by sol-gel technique was investigated by using in situ second harmonic generation (SHG) measurement.SHG signal came from the doped hemicyanine molecules which automatically oriented in the film.We found that the SHG measurement can be used as a semi-quantitatively probe of the gelling process.The time of gelling was found to depend sensitively on the annealing temperatures.Film shrinkage during gelling resulted in disordering of the doped hemicyanine molecules,consequently,SHG intensity decreased during annealing.