Glass - Back to the Future!

Presenting Author:
Alexey Novikov

article posted 06 April 2016

Alexey NovikovBeing a second year PhD student I study Sr, Ba and Zn aluminosilicates with the aim to describe structural changes caused by changes in the composition. I intend to find a link between observed macroscopic properties and spectroscopic responses. For my studies I synthesize glasses and ceramics and then investigate them by means of Raman, NMR, XAS, X-ray/neutron diffraction. Among the macroscopic properties I measure there are density, viscosity and glass transition temperature.

BaO–Al2O3–SiO2 glasses and melts: from nano- to macroscale

Alexey Novikov1,2*, Pierre Florian1, Daniel R. Neuville2
1CNRS-CEMHTI, 1D avenue de la Recherche Scientifique, 45000 Orléans, France
2CNRS-IPGP, Géomatériaux, Paris Sorbonne Cité, 1 rue Jussieu, 75005 Paris, France

Understanding the macroscopic properties of aluminosilicates is essential for describing geological processes, predicting magmas behaviour and modes of eruption. In industrial processes of glass and glass-ceramics manufacturing, viscosity plays a vital role as well. Along with viscosity, configurational entropy, Sconf provides fundamental information on melt behaviour and glass forming processes.
Among alkaline earth aluminosilicates, the ones composed of barium have a disturbed network due to the large size of the barium cation as compared to Sr, Ca or Mg. To study the effect of the composition of BaO–Al2O3–SiO2 on their macroscopic properties, series of barium aluminosilicate glasses with different BaO/Al2O3 ratios and silica content were studied by viscometry at low temperatures. The experimental data was then fitted using the Vogel-Fulcher-Tammann equation in order to obtain Tg. Further Sconf was calculated using the results at low temperature and available data on high temperature viscosity. The following equation was used: logeta = Ae + Be/(T·Sconf), where eta is viscosity, T – temperature, Ae and Be are constants.
In addition to the macroscopic measurements, Raman and NMR spectroscopies were used to study medium- and short-range order. The results of this study will be presented, discussed and compared with previous data on other alkaline earth aluminosilicates.