Development of refractive-index change polymers by external stimuli

材料的折射率可调可控是当今光学应用的重要关键技术，如开关、数据存储设备等。由于对这类材料的需求不断增加，我们将重点放在基于光反应功能聚合物的无任何释放产物的折射率变化材料上。我们发现，在加热过程中，S-(2-苯并恶唑基)硫酯转变为苯并唑啉-2-硫酮，由于产生了极性官能团C=S键，从而提高了折射率。我们设计并合成了含有两个S-(2-苯并恶唑基)硫代酯基团的新单体，以增强折射率的变化。此外，通过二甲酰基衍生物与二氨基衍生物的直接缩合反应和自由基聚合法合成了主链和侧链上都含有水杨酰亚胺基团的聚合物。由于这些聚合物的非晶态结构，它们的色度很难检测到。

Tunable and controllable refractive index of materials is important key technology in today's optical application such as switches, and data storage devices. Due to the increasing demand for such materials, we focused on the refractive index change materials without any release products based on photoreactive functional polymers. We found that the structural change from S-(2-benzoxazolyl) thioester to bezoxazoline-2-thione under heating increase the refractive index due to the production of the polar functional C=S bond. We designed and synthesized new monomers containing two S-(2-benzoxazolyl) thioester groups in order to enhance the change in refractive index. Also, polymers containing salicylideneaniline groups both in the main chain and in the side chain were prepared by the direct condensation reaction of diformyl derivatives with diamino derivatives and by radical polymerization, respectively. The chromism of these polymers was hard to detect due to their amorphous structure.