Effect of the replacement of aluminum by magnesium on the compressibility and degree of polymerization of silicate glasses

• Published in: Journal of materials science 2013-06, Vol.48 (12), p.4416-4426
• Main Authors: Kuryaeva, R. G., Surkov, N. V.
• Format: Article
• Language: English
• Subjects: Aluminum; Anvils; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Compressibility; Crystallography and Scattering Methods; Degree of polymerization; Density; Depolymerization; Diamonds; Glass; Magnesium; Materials Science; Photoelasticity; Polymer Sciences; Polymerization; Refractivity; Silicates; Solid Mechanics
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-013-7260-6

The refractive index of Na 2 MgSi 4 O 10 and Na 2 Al 2 Si 4 O 12 glasses in the pressure range to 6.0 GPa was measured using a polarization-interference microscope and apparatus with diamond anvils. The changes in relative density, which characterize the compressibility of glasses, were calculated in the studied range of pressures from the measured refractive indices within the framework of the theory of photoelasticity. For the studied glasses, the degree of depolimerization was found to be NBO / T  = 0.28 and 0.25 for Na 2 MgSi 4 O 10 and Na 2 Al 2 Si 4 O 12 glasses, respectively. It is shown that the replacement of aluminum by magnesium in silicate glasses does not lead to a considerable decrease in compressibility, which suggests the predominant role of magnesium ions as network formers. A minor increase in compressibility when passing from Na 2 MgSi 4 O 10 to Na 2 Al 2 Si 4 O 12 glass conforms with the corresponding decrease in the degree of depolymerization.