Characterisation and thermal behaviour of a borosilicate glass

• Published in: Thermochimica acta Vol. 373; no. 1; pp. 69 - 74
• Main Authors: Lima, M.M, Monteiro, R
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2001; Elsevier Science
• Subjects: Applied sciences; Borosilicate glass; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Cristobalite precipitation; Exact sciences and technology; Glasses; Structure, analysis, properties; Thermal properties; Viscous flow; Thermal properties; Borosilicate glass; Cristobalite precipitation; Viscous flow; Viscosity; Chemical precipitation; Differential thermal analysis; X ray diffraction; Glass transition temperature; Aluminium Oxides; Cristobalite; Dilatometry; Potassium Oxides; Boron Oxides; Sintering; Thermal expansion coefficient; Silicon Oxides; Sodium Oxides; Thermal analysis; Rheological properties
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/S0040-6031(01)00456-7

The changes occurring during the heating of a borosilicate glass have been investigated by differential thermal analysis, dilatometric analysis and thermomechanical analysis. The thermal properties of this glass, such as glass transition temperature, dilatometric softening temperature and linear thermal expansion coefficient, have been determined. Viscosity measurements in the temperature range 898–1048 K were performed in a thermomechanical analyser equipped with a penetration attachment for isothermal measurement, and from the temperature dependence of viscosity a value of 290 kJ mol −1 was obtained for the activation energy for viscous flow. Devitrification of the glass was observed, specifically in finely powdered glass samples, where the precipitation of cristobalite was identified by X-ray diffraction. Glass powder compacts sintered by viscous flow and cristobalite precipitation reduced strongly the shrinkage rate.