Structural origin of thermal shrinkage in soda-lime silicate glass below the glass transition temperature: A theoretical investigation by microsecond timescale molecular dynamics simulations

被引：6

作者：

Shimizu, Masahiro ^{[1
]}

Murota, Teppei ^{[1
]}

Urata, Shingo ^{[2
]}

Takato, Yoichi ^{[2
]}

Hamada, Yuya ^{[2
]}

Koike, Akio ^{[2
]}

Shimotsuma, Yasuhiko ^{[1
]}

Fujita, Koji ^{[1
]}

Miura, Kiyotaka ^{[1
]}

机构：

[1] Kyoto Univ, Grad Sch Engn, Dept Chem Mat, Nishikyo Ku, Kyoto 6158510, Japan

[2] AGC Inc, Yokohama, Kanagawa 2218755, Japan

来源：

JOURNAL OF CHEMICAL PHYSICS | 2021年 / 155卷 / 04期

基金：

日本学术振兴会;

关键词：

MODEL; RELAXATION;

D O I：

10.1063/5.0056464

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Microscopic dynamical features in the relaxation of glass structures are one of the most important unsolved problems in condensed matter physics. Although the structural relaxation processes in the vicinity of glass transition temperature are phenomenologically expressed by the Kohlrausch-Williams-Watts function and the relaxation time can be successfully interpreted by Adam-Gibbs theory and/or Narayanaswamy's model, the atomic rearrangement, which is the origin of the volume change, and its driving force have not been elucidated. Using the microsecond time-scale molecular dynamics simulations, this study provides insights to quantitatively determine the origin of the thermal shrinkage below T-g in a soda-lime silicate glass. We found that during annealing below T-g, Na ions penetrate into the six-membered silicate rings, which remedies the acute O-O-O angles of the energetically unstable rings. The ring structure change makes the space to possess the cation inside the rings, but the ring volume is eventually reduced, which results in thermal shrinkage of the soda-lime silica glass. In conclusion, the dynamical structural relaxation due to the cation displacement evokes the overall volume relaxation at low temperature in the glassy material.

引用

页数：11