基于光致聚合物材料曝光后横向收缩与厚度收缩引起光栅矢量大小和方向的变化,导出了光致聚合物的收缩率与光栅读出角的布拉格偏移之间的显性关系。并设计了两步实验法,采用蓝光记录、红光动态扫描读出,分别对光致聚合物中的非倾斜光栅和倾斜光栅的布拉格偏移进行了实验测量。对自行研制的两种新型蓝光敏感光致聚合物样品,测量了其横向与厚度的收缩率,求出了材料的体积收缩率,其中经过优化配比的样品体积收缩率小于0.5%。实验也表明材料的横向收缩一般是不能忽略的。通过这种简明可靠的收缩率测量方法,可较快确定大量光致聚合物样片的收缩率,有助于找出收缩率与材料组分的关系。

An explicit relation between the Bragg shift of the grating readout angle and the shrinkage of photopolymer samples is presented based on the changes in amplitude and direction of the grating vector, caused by lateral shrinkage and thickness shrinkage of photopolymer after exposure. A two-step experimental method to measure the Bragg shift of the unslanted grating and slant grating in photo polymer separately is designed and implemented with blue light readin and red light readout. The lateral shrinkage and thickness shrinkage of two self-made blue-light photopolymer samples are calculated respectively, and their volume shrinkage are obtained. The results show that the volume shrinkage of the sample with modified composition is less than 0.5%. This study also shows that the lateral shrinkage of photopolymer is generally not negligible. By using this method, it is easier to measure the shrinkage of a large amount of photopolymer samples, and find the relation between shrinkage and compositions of photopolymer.