The race within supercooled liquids-Relaxation versus crystallization

Autor(es)

Zanotto, Edgar D. ^[1] ; Cassar, Daniel R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Vitreous Mat Lab, Dept Mat Engn, Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Chemical Physics; v. 149, n. 2 JUL 14 2018.
• Citações Web of Science: 3

Resumo

Can any liquid be cooled down below its melting point to an isentropic (Kauzmann) temperature without vitrifying or crystallizing? This long-standing question concerning the ultimate fate of supercooled liquids is one of the key problems in condensed matter physics and materials science. In this article, we used a plethora of thermodynamic and kinetic data and well established theoretical models to estimate the kinetic spinodal temperature, T-KS (the temperature where the average time for the first critical crystalline nucleus to appear becomes equal to the average relaxation time of a supercooled liquid), and the Kauzmann temperature, T-K, for two substances. We focused our attention on selected compositions of the two most important oxide glass-forming systems: a borate and a silicate-which show measurable homogeneous crystal nucleation in laboratory time scales-as proxies of these families of glass-formers. For both materials, we found that the T-KS are significantly higher than the predicted T-K. Therefore, at ambient pressure, at deep supercoolings before approaching T-K, crystallization wins the race over structural relaxation. Hence, the temperature of entropy catastrophe predicted by Kauzmann cannot be reached for the studied substances; it is averted by incipient crystal nucleation. Our finding that T-KS > T-K for two real glasses corroborate the results of computer simulations for a pressurized silica glass. Published by AIP Publishing. (AU)

• 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
• Processo FAPESP: 17/12491-0 - Processos cinéticos em vidros e novas formulações vítreas via aprendizagem de máquina
• Beneficiário: Daniel Roberto Cassar
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado