Aging-Induced Structural Evolution of a GeSe 2 Glass Network: The Role of Homopolar Bonds
Aging-Induced Structural Evolution of a GeSe 2 Glass Network: The Role of Homopolar Bonds
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GeSe 2 玻璃网络的老化引起的结构演化：同极性键的作用
DOI：
10.1021/acs.jpcb.1c08836
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Sen, Sabyasachi
中科院分区：
文献类型：
--
作者：
Yuan, Bing;Chen, Hao;Sen, Sabyasachi
利用拉曼光谱和密度弛豫测量研究了GeSe 2玻璃在老化过程中的结构演变。拉曼光谱表明，在低于标称玻璃化转变温度65 °C下老化期间，角共享（CS）和边共享（ES）GeSe 4四面体的相对浓度以及四面体网络的化学有序度发生体积和熵驱动的变化。伴随的结构变化涉及CS：ES比的逐渐增加和化学顺序的逐渐增加，其可以以反应Ge-Ge + Se-Se → 2 Ge-Se的形式表示，该反应随着假想温度的降低而向右移动。在老化过程中的结构和密度的等温弛豫表现出相当相似的拉伸指数动力学，拉伸指数β为0.54，平均弛豫时间为13.5 h。原位高温拉曼光谱测量表明，结构弛豫不影响GeSe 2玻璃的能量景观中的振动势威尔斯的非谐性。
The structural evolution of GeSe2glass during aging is studied using Raman spectroscopy and density relaxation measurements. The Raman spectra indicate volume- and entropy-driven changes in the relative concentrations of the corner-sharing (CS) and edge-sharing (ES) GeSe4tetrahedra and in the degree of chemical order of the tetrahedral network during aging at 65 °C below the nominal glass transition temperature. The attendant structural changes involve a progressive increase in the CS:ES ratio and in the chemical order that can be expressed in the form of a reaction Ge–Ge + Se–Se → 2 Ge–Se, which shifts to the right, with lowering of fictive temperature. The isothermal relaxation of both the structure and density during aging displays rather similar stretched exponential kinetics with a stretching exponent β ∼0.54 and an average relaxation time of ∼13.5 h.In situhigh-temperature Raman spectroscopic measurements indicate that structural relaxation does not affect the anharmonicity of the vibrational potential wells in the energy landscape of GeSe2glass.