不同生色团对聚合物薄膜全光开关效应的影响

Influence of Doping Different Azo Chromophores on the All-Opt ical Switching Effect of the Polymer Films

在聚甲基丙烯酸甲酯 (PMMA)中掺入不同的偶氮染料并制成薄膜样品 ,以调制的线偏振Ar+ 激光(5 14nm ,CW)作为控制光 ,He Ne激光 (6 32 .8nm ,CW)为信号光 ,研究了样品的光致双折射效应及全光开关效应。通过对样品的响应特性和全光开关效应进行比较 ,发现电子推拉势较强的生色团分子在控制光作用下 ,可以产生较大的光致双折射效应 ,但光响应速度较慢 ,其光致双折射效应以光致异构取向为主要机制 ;而对于具有较弱电子推拉势的生色团分子 ,其光致双折射效应则主要来自光致异构烧孔机制 ,虽然其光致双折射效应小 ,但光响应速度快。

Different samples were prepared by doping azo dy e 4'-[[2-(acryloyloxy) ethyl] ethylamino]-4-nitroazobenzene (DR1), 4'- [[2-(acryloyloxy) ethyl] ethylamino]-2-chloro-4-nitroazobenzene (DR13) and 4'-[2-2-(acryloyloxy) ethyl]-4-nitroazobenzene (DR19) in poly (methyl methacrylate) (PMMA) polymer films. The optical switching effects of the compos ites were measured by using linearly polarized 514 nm pump beam from an Ar+ la ser (514 nm,CW) and a linearly polarized probe beam from a He-Ne laser (632.8 n m, CW). It was found that the sample containing the chromophores with strong pul l/push electronic potential showed larger birefringence but slow response, which mainly came from the photoinduced reorientation process of the chromophores. The sample containing the chromophores with weak pull/push electronic potential showed small birefringence but fast response, which was attributed to the faster angular hole burning process of the chromophores.