Effect of K2O on structure–property relationships and phase transformations in Li2O–SiO2 glasses

摘要: Abstract Glass compositions with formula (71.78 − x)SiO2–2.63Al2O3–(2.63 + x)K2O–23.7Li2O (mol.%, x = 0–10) and SiO2/Li2O molar ratios far beyond that of stoichiometric lithium disilicate (Li2Si2O5) were prepared by conventional melt-quenching technique to investigate the influence K2O content on structural transformations devitrification behaviour glasses in Li2O–SiO2 system. The scanning electron microscopy (SEM) examination as cast non-annealed revealed presence nanosized droplets glassy matrices suggesting occurrence liquid–liquid phase separation. An overall trend towards depolymerization silicate glass network increasing was demonstrated employing magic angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopy. distribution units experimental estimated using 29Si MAS-NMR spectroscopy appearance Q2, enhancement Q3 diminishing Q4 groups contents. X-ray diffraction (XRD) differential thermal analysis (DTA) used assess process formation and/or metasilicate (Li2SiO3) crystalline phases.