| Texto completo | |
| Autor(es): |
Lancelotti, Ricardo F.
;
Zanotto, Edgar D.
;
Sen, Sabyasachi
Número total de Autores: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Journal of Chemical Physics; v. 160, n. 3, p. 10-pg., 2024-01-21. |
| Resumo | |
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) | |
| Processo FAPESP: | 22/07679-8 - Origem em escala atômica da relaxação estrutural de vidros metassilicato de chumbo e dissilicato de lítio |
| Beneficiário: | Ricardo Felipe Lancelotti |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Doutorado |
| Processo FAPESP: | 21/03374-5 - Relaxação estrutural de vidros e sua influência em outros processos dinâmicos |
| Beneficiário: | Ricardo Felipe Lancelotti |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros |
| Beneficiário: | Edgar Dutra Zanotto |
| Modalidade de apoio: | Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs |