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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Raman scattering and molecular dynamics investigation of lead metasilicate glass and supercooled liquid structures

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Sampaio, V, D. ; Picinin, A. [1] ; Moulton, Benjamin J. A. [1] ; Rino, J. P. [1] ; Pizani, P. S. [1] ; Zanotto, E. D. [2]
Total Authors: 6
[1] Sampaio, D., V, Univ Fed Sao Carlos, Dept Fis, Caixa Postal 676, BR-13565905 Sao Carlos, SP - Brazil
[2] Univ Fed Sao Carlos, Dept Engn Mat, Caixa Postal 676, BR-13565905 Sao Carlos, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Journal of Non-Crystalline Solids; v. 499, p. 300-308, NOV 1 2018.
Web of Science Citations: 0

In this research we correlate the structural parameters obtained from molecular dynamics (MD) simulations and Raman scattering to construct a self-consistent picture of the glass structure, and its variation from ambient temperature to the supercooled liquid above the glass transition temperature (Tg). The MD results show that the glass structure is composed of SiO4 tetrahedra and PbOx (x = 4, 5) polyhedra. To correlate the Q(n) population obtained from the MD and Raman a second type of Q(3) species is required. The two types of Q(3) species are interpreted as being associated with the bimodal distribution displayed by the Pb-Si pair correlation function. From a MD snapshot is also shown that the second Q(3) species can have a bridging oxygen bound to a Pb ion. As the temperature increases, depolymerization of the Q(n) speciation is observed and confirmed by the oxygen speciation determined from both Raman and MD. The depolymerization of the silica network is consistent with the non-Arrhenian (fragile) viscosity decrease with temperature and may explain this viscosity behavior. (AU)

FAPESP's process: 16/15962-0 - Correlation between materials structure and dynamic and optical properties of (Ax, A'1-x)O + SiO2 (A, A' = Pb, Ni, Co, Fe, Cr) series: Raman scattering and molecular dynamics simulations
Grantee:David Vieira Sampaio
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass
Grantee:Edgar Dutra Zanotto
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 16/18567-5 - Nuclei entrapment: the pre-nucleation structural ordering of homogeneous nucleating BaO-2SiO2 and CaO-SiO2 glasses
Grantee:Benjamin John Albert Moulton
Support type: Scholarships in Brazil - Post-Doctorate