Relaxation Dynamics in Selenide-Based Chalcogenide Glasses: Characterization of the Intermediate Phase

在这个由化学系化学结构、动力学和机制计划资助的项目中，德克萨斯理工大学的Sindee L.Simon和Gregory B.McKenna将使用量热法、动态热谱、剪切和块体流变学以及纳米流变学来研究硒系硫化物玻璃的弛豫动力学。讨论了三个重要的科学问题：玻璃在接近和在中间相区老化时的稳定性，纳米约束和压力对动力学的影响，以及超薄膜异常机械硬化的起源。特别令人感兴趣的是测量老化过程中的热恢复和蠕变作为组成、温度和老化时间的函数，目的是更全面地了解这些玻璃的稳定性与组成的关系。更广泛的影响包括培训两名研究生，将新材料融入到私人投资机构教授的课程中，以及通过为小学生举办的“超级星期六”丰富计划和为初中和高中女孩举办的暑期“科学--这是女孩的事情”计划，向五年级到十一年级的年轻学生推广。硫系玻璃的物理和化学稳定性在其许多潜在应用中非常重要，包括作为存储设备、光波导和太阳能电池。通过增加对Boolchand中间相的了解，提高了稳定性，预计结果将有助于合成用于此类应用的稳定的硫系玻璃。

In this project funded by the Chemical Structure, Dynamics, and Mechanisms Program of the Chemistry Division, Sindee L. Simon and Gregory B. McKenna of Texas Tech University will investigate the relaxation dynamics in selenide-based chalcogenide glasses using calorimetry, dynamic heat spectroscopy, shear and bulk rheology, and nanorheology. Three important scientific issues are addressed: the stability of the glasses with respect to aging near and in the intermediate phase region, the effects of nanoconfinement and pressure on the dynamics, and the origin of the unusual mechanical stiffening of ultrathin films. Of particular interest is the measurement of enthalpy recovery and creep during aging as a function of composition, temperature, and aging time aimed at a more complete understanding of the composition dependence of the stability of these glasses. Broader impacts include training of two graduate students, incorporation of new material into courses taught by the PIs, and outreach to young students, from fifth through eleventh grades, through a "Super Saturdays" enrichment program for grade-school children and a summer "Science - It's a Girl Thing" program for junior-high and high-school girls.The physical and chemical stability of chalcogenide glasses are important in many of their potential applications, including as memory devices, optical waveguides, and solar cells. By increasing understanding the Boolchand intermediate phase, which has enhanced stability, the results are anticipated to facilitate synthesis of stable chalcogenide glasses for such applications.