POWRE: Relaxation Study of a Trigonal Network Glass

该项目是对玻璃状氧化硼的结构和弛豫的分子动力学模拟研究，玻璃状氧化硼属于一般的网络玻璃，具体地说是由三角配位的硼原子组成。该研究的长期目标是建立网络玻璃的短程有序（维度或配位）与玻璃化转变相关的物理性质之间的关系。该建议的基础是具有三重配位的材料的松弛行为。弛豫速率的快速下降和复杂动力学的开始，如非指数弛豫是进入玻璃态的普遍特征之一。具有四重（二氧化硅玻璃）和两重（线性聚合物）配位的材料比三重配位的材料（如B2O3）得到了更广泛的研究。B_2O_3的中程有序也是令人感兴趣的。实验已经揭示了六元硼氧环的存在，但模拟研究的证实只遇到了有限的成功。工作将分两个阶段进行：表征B_2O_3的结构和研究再结晶。一个有前途的模型，包括许多身体的极化效应正在适应研究B2O3，因为它描述的极化效应已被证明是必要的一个现实的模型，氧化硼。该模型将用于研究硼氧化物的结构，特别是硼氧环的问题。随后将对B2O3的弛豫进行全面表征。这是根据研究和教育领域女性专业机会（POWRE）方案提供的研究增强补助金。拟定的探索性研究活动为PI定义了一个新的关注领域。该项目将允许PI将她在分子模拟领域的专业知识应用于玻璃科学中的问题。这项研究有望在与玻璃材料行为特别相关的基础层面上贡献基础材料科学知识。该项目由材料研究部和MPS OMA（多学科活动办公室）共同支持。***

This project is a molecular dynamics simulation study of the structure and relaxation of vitreous boron oxide, which belongs to the general class of network glasses, and specifically consists of trigonally coordinated boron atoms. The long term goal of the research is to establish a relation between short range order (dimensionality or coordination) of network glasses and physical properties relevant to the glass transition. The basis of the proposal is the relaxation behavior of a material with three-fold coordination. A rapid decrease in relaxation rates and the onset of com-plex dynamics such as non-exponential relaxation is one of the universal signatures of entrance to the glassy state. Materials with four-fold (silica glass) and two-fold (linear polymers) coordi-nation have been more extensively studied than three-fold coordinated materials such as B2O3. The intermediate range order of B2O3 is also of interest. Experiments have revealed the existence of six member boroxol rings, but confirmation with simulation studies has met only limited suc-cess. The work will proceed in two phases: characterizing the structure of B2O3 and studying re-laxation. A promising model that includes many body polarization effects is being adapted to study B2O3 since the polarization effects it describes have been shown necessary for a realistic model of boron oxide. This model will be used to investigate the structure of boron oxide, spe-cifically the question of boroxol rings. Full characterization of the relaxation of B2O3 will follow. %%% This is a research enhancement grant made under the Professional Opportunities for Women in Research and Education (POWRE) program. The exploratory research activity proposed defines a new area of interest for the PI. The project will allow the PI to apply her expertise in the area of molecular simulation to problems in glass science. The research is expected to contribute basic materials science knowledge at a fundamental level of special relevance to the behavior of glassy materials. The project is co-supported by the Division of Materials Research, and the MPS OMA(Office of Multidisciplinary Activities). ***