Experimental Studies of the Liquid-Glass Transition

液体-玻璃转变的实验研究

• 批准号: 9980370
• 负责人: Herman Cummins
• 金额: --
• 依托单位: CUNY City College
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9980370&HistoricalAwards=false
• 关键词: Experimental; Studies; Liquid; Glass; Transition

9980370CumminsThis project investigates the dynamics of liquids in the vicinity of the liquid-glass transition and of solid glasses by laser light scattering spectroscopy. Recent theoretical and experimental research has shown that relaxation (or memory) functions in supercooled liquids exhibit complex behavior extending over many decades in frequency. Current research is directed at measuring these functions and their evolution with decreasing temperature. The data analysis will utilize an extension of mode coupling theory (MCT) that now includes orientational degrees of freedom. A systemic investigation of both polarized and depolarized Brillouin scattering in the molecular glass-former salol will be carried out to explore the extent to which relaxation functions can be determined reliably with this technique. They will be used to assess the compatibility of such results with MCT, which provides detailed predictions for density correlation functions and their evolution with temperature. In addition, the dynamics of glasses at lower temperatures where aging phenomena and two-time scaling behavior has been predicted theoretically and observed in computer simulations will be pursued. The techniques developed will also be applied to new materials including elastomers, materials in which the liquid and glass phases are separated by an intermediate elastomer (or rubber) phase.%%%The liquid-glass transition is one of the oldest unresolved fundamental problems in condensed matter physics. It is also of major practical concern in the manufacture of various glasses including plastics and glassy metallic alloys. Current mode coupling theories will be tested to assess the extent to which relaxation (or memory) functions can be determined reliably with this technique. In addition, the dynamics of glasses at lower temperatures where aging phenomena and two-time scaling behavior has been predicted theoretically and observed in computer simulations will be pursued. The techniques developed will also be applied to new materials including elastomers, materials in which the liquid and glass phases are separated by an intermediate elastomer (or rubber) phase.This research project utilizes laser light-scattering techniques and will be conducted by primarily by graduate students and postdoctoral researchers. The program will include collaborations with other research groups both in the US and in Europe.***

9980370康明斯这个项目用激光光散射光谱研究了液体-玻璃转变附近的液体和固体玻璃的动力学。最近的理论和实验研究表明，过冷液体中的弛豫(或记忆)函数表现出频率长达数十年的复杂行为。目前的研究方向是测量这些函数及其随温度下降的演化。数据分析将利用现在包括定向自由度的模式耦合理论(MCT)的扩展。我们将对分子玻璃成形器Salol中的极化和去极化布里渊散射进行系统的研究，以探索这种技术在多大程度上可以可靠地确定弛豫函数。它们将被用来评估这些结果与MCT的兼容性，MCT提供了对密度关联函数及其随温度变化的详细预测。此外，还将继续研究玻璃在较低温度下的动力学，其中老化现象和两次标度行为已经从理论上预测出来，并在计算机模拟中观察到。开发的技术还将应用于新材料，包括弹性体，即液体和玻璃相由中间弹性体(或橡胶)相分开的材料。液体-玻璃转变是凝聚态物理学中最古老的尚未解决的基本问题之一。在包括塑料和玻璃金属合金在内的各种玻璃的制造中，它也是一个主要的实际问题。目前的模式耦合理论将被测试，以评估使用这项技术可以可靠地确定松弛(或记忆)功能的程度。此外，还将继续研究玻璃在较低温度下的动力学，其中老化现象和两次标度行为已经从理论上预测出来，并在计算机模拟中观察到。开发的技术还将应用于新材料，包括弹性体，即液体和玻璃相被中间弹性体(或橡胶)相分开的材料。这项研究项目利用激光散射技术，主要由研究生和博士后研究人员进行。该计划将包括与美国和欧洲的其他研究小组的合作。