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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.)

A Raman investigation of the structural evolution of supercooled liquid barium disilicate during crystallization

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Moulton, Benjamin J. A. [1, 2] ; Rodrigues, Alisson Mendes [2] ; Pizani, Paulo Sergio [1, 2] ; Sampaio, David Vieira [1, 2] ; Zanotto, Edgar Dutra [2]
Total Authors: 5
[1] Univ Fed Sao Carlos, Dept Fis, Sao Carlos, SP - Brazil
[2] Univ Fed Sao Carlos, CERTEV Ctr Res Technol & Educ Vitreous Mat, Dept Mat Engn, Sao Carlos, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Web of Science Citations: 1

The homogeneous and stoichiometric crystallization of the barium disilicate (BaSi2O5) glass makes it possible to follow the structural evolution of Raman bands from the supercooled liquid to the crystalline phase. We monitored the crystallization of supercooled liquid BaSi2O5 at 790 degrees C over 440minutes revealing a three-stage crystallization process: stage 1 involves changes in the barium sites toward a bonding environment that is similar to that in orthorhombic low barium disilicate. The end of stage 1 is marked by the loss of the Q(4) species vibration at 1170cm(-1) and the creation of a crystalline band at 490cm(-1). Stage 2 is marked by the transition of the Q(3) peak (1060cm(-1)) from a Gaussian-like to a Lorentzian curve, indicating the formation of well-developed sheet structures. These observations lead us to conclude that the Raman spectra are resolving both the crystalline L-BS2 phase and the BS2 melt. The final stage involves a rapid decrease in the remaining Q(n) species to form Q(3). This crystallization process involves structural modifications that occur on the tens of microns scale. The barium cations drive the initial stages of crystallization, providing direct evidence that the short-range order, around network modifiers, is a critical factor involved in homogeneous crystallization. (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