两类玻璃中与玻璃转变关联的结构弛豫内耗研究

Glass transition, as an universal phenomenon in nature, is one of the most important basic problems unsolved in current condensed matter physics. The accumulated studies have confirmed that the mechanism of the structual relaxation related to the glass transition in glass formers is the key to understand the glass transition. Among the very wide spectra of glass formers, metallic glasses and SiO2/GeO2 based oxide glasses containing alkali and oxygen ions are ones of the simplest glass formers with clear microstructure, and offer a good opportunaty to understand the mechanism of the structural relaxation. The aim of this application is to clarify the mechanism of the structural relaxation in the two types of glass formers with the detailed measurements of internal fiction (dynamical mechanic structrual relaxation). Through the temperature, probing time/frequecy and composition dependence of the primary structural relaxation in supercooled liquid and possible secondary relaxation in glass the intrinsic relation between the two types of relaxation can be founded. Furhtermore, the basic motion of structural relaxations in the two types of glass formers can be deduced with their clear microstructure. Then, with the superposition of motions in statistical physics and the relation between the basic motion and the whole structural relaxation we will build up the theoretical framework of the structural relaxation related to the glass transition. This study would offer a strong experimental and theoretical evidence to understand further the problem of the glass transition in these glass formers.

玻璃转变，普遍存在的一个基本自然现象，仍是一个现凝聚态物理中尚未解决的最重要的基本难题。大量研究表明解决玻璃转变问题的关键在于与其密切关联的结构弛豫机理认知。众多的玻璃体系中，金属玻璃和SiO2/GeO2为基添加碱金属和氧离子的氧化物玻璃有着明晰的简单结构特征，是结构弛豫机理研究的理想材料。本课题以解析这两类玻璃体系中结构弛豫机理为研究目标，采用内耗（动态力学测试）为研究手段和方法，系统而详尽地获得玻璃转变密切关联的结构弛豫谱；通过深过冷液体中的主结构弛豫和可能的玻璃中次级结构弛豫谱与测量温度、时间/频率和成分的关系确立它们之间的本征关联性；根据这两类玻璃体系结构基本特征，寻找引发结构弛豫的基本运动特征；由此根据统计物理中运动的叠加原理和基本运动与整体结构弛豫行为的关联性，建立普适性的玻璃转变密切关联结构弛豫基本理论框架。研究将为认识这两类玻璃中的玻璃转变本质提供坚实的实验和理论基石。

本项目的研究背景是现凝聚态物理中的一个尚未解决且最重要的基本难题—玻璃转变。尽管玻璃转变是普遍存在的基本自然现象，只要液体的晶化被抑制，冷却结果必然形成玻璃。大量研究表明玻璃转变本质问题解决的关键在于接近玻璃转变温区的深过冷液体中的复杂结构弛豫机理的澄清。众多玻璃体系中，金属玻璃和SiO2/GeO2为基添加碱金属氧化物的常见氧化物玻璃有着明晰的简单微观结构特征，是结构弛豫机理研究的理想材料。本项目是以解析这两类玻璃体系中结构弛豫机理为研究目标，采用内耗（动态力学测试）为研究手段和方法，系统而详尽地获取玻璃转变相关联的结果弛豫谱；通过深过冷液体中主弛豫和可能的玻璃次弛豫与测量温度、时间/频率以及成分等的关系，确立结构弛豫的影响因素；根据这两类玻璃体系结构基本特征，探索出引发结构弛豫的基本运动特征；依据理论分析，建立普适性的玻璃转变密切关联的结构弛豫基本理论框架。研究为认识这两类玻璃中玻璃转变本质的澄清提供了有力的实验和理论支撑。