| Full text | |
| Author(s): |
Lancelotti, Ricardo F.
;
Zanotto, Edgar D.
;
Sen, Sabyasachi
Total Authors: 3
|
| Document type: | Journal article |
| Source: | Journal of Chemical Physics; v. 160, n. 3, p. 10-pg., 2024-01-21. |
| Abstract | |
In this article, we investigate the structural relaxation of lithium silicate glass during isothermal physical aging by monitoring the temporal evolution of its refractive index and enthalpy following relatively large (10-40 degrees C) up- and down-jumps in temperature. The Kohlrausch-Williams-Watts function aptly describes the up- and down-jump data when analyzed separately. For temperature down-jumps, the glass exhibits a typical stretched exponential kinetic behavior with the non-exponentiality parameter beta < 1, whereas up-jumps show a compressed exponential behavior (beta > 1). We analyzed these datasets using the non-exponential and non-linear Tool-Narayanaswamy-Moynihan (TNM) model, aiming to provide a comprehensive description of the primary or alpha-relaxation of the glass. This model described both up- and down-jump datasets using a single value of beta <= 1. However, the standard TNM model exhibited a progressively reduced capacity to describe the data for larger temperature jumps, which is likely a manifestation of the temperature dependence of the non-exponentiality or non-linearity of the relaxation process. We hypothesize that the compressed exponential relaxation kinetics observed for temperature up-jumps stems from a nucleation-growth-percolation-based evolution on the dynamically mobile regions within the structure, leading to a self-acceleration of the dynamics. On the other hand, temperature down-jumps result in self-retardation, as the slow-relaxing denser regions percolate in the structure to give rise to a stretched exponential behavior. (AU) | |
| FAPESP's process: | 22/07679-8 - Atomistic origin of structural relaxation in lead metasilicate and lithium disilicate glasses |
| Grantee: | Ricardo Felipe Lancelotti |
| Support Opportunities: | Scholarships abroad - Research Internship - Doctorate |
| FAPESP's process: | 21/03374-5 - Structural relaxation of glass and its influence on other dynamic processes |
| Grantee: | Ricardo Felipe Lancelotti |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass |
| Grantee: | Edgar Dutra Zanotto |
| Support Opportunities: | Research Grants - Research, Innovation and Dissemination Centers - RIDC |