硫系玻璃具有极高的三阶非线性系数和极宽的红外透过区域，它可以作为一种新型红外光子器件（光纤、波导等）基质材料在中红外光学方面具有广阔的应用前景，深入研究硫系玻璃的微观结构对于进一步优化其性能具有重要的意义，但目前国内外对于硫系玻璃结构的研究大多是针对在室温的情形，缺乏在高温尤其是玻璃转变温度附近玻璃的结构信息。本项目拟采用反蒙特卡洛与分子动力学相结合的方法，对中子衍射实验已测得的不同温度下的玻璃结构因子进行模拟，构建准确的非晶态硫系玻璃转变前后的微观结构。通过对比研究不同温度下硫系玻璃网络结构中原子的排列方式，从而分析微观结构中短程有序随着温度的变化规律，尤其是研究对玻璃光学损耗具有极大影响的同极键的数目随温度的变化行为，从而探寻抑制硫系玻璃微观结构中同极键形成的最佳条件，为制备高质量、低损耗的硫系玻璃提供理论依据。

Chalcogenide glasses have large third order optical nonlinearity and wide transmission range, and thus they offer great potentials as materials used in the photonics devices in the mid-infrared. Research in glass structure is important to further improvement of glass properties. However previous research in glass structure was usually performed at room temperature, there is almost no report on structural information at high temperature, especially near glass transition temperature. Therefore in this project, we will develop new method combining the Reverse Monte Carlo method and molecular dynamics to simulate the structural factors obtained from neutron scattering experiments, and build exact structural model for the glass near the glass transition temperature. We will analyze the temperature dependence of short range order via comparing the atomic arrangement in the glass network, especially the temperature dependence of the number of homopolar bonds that can significantly affect the optical losses of the glasses. We will explore the optimal conditions to suppress the formation of the homopolar bonds. The results achieved in the project will form a solid base for the preparation of high quality chalcogenide glasses with low optical losses.