Intermediate-Range Order of Alkali Disilicate Glasses and Its Relation to the Devitrification Mechanism

Abstract

There are two general mechanisms of devitrification in glass: heterogeneous nucleation of crystals from surfaces and impurities and homogeneous nucleation from the volume. It is thought that structural similarities between glass and crystal at the intermediate-range level influence the mechanism followed; however, there are scarce experimental studies to test this hypothesis. In this paper solid-state nuclear magnetic resonance spectroscopy is used to probe intermediate-range order in sodium and lithium disilicate glasses through measurement of the second moment of the distribution of dipolar couplings. These two glasses undergo heterogeneous and homogeneous nucleation, respectively. The second moments measured for the lithium glass closely follow the trend established by the layered structures of the isochemical crystalline phases, while the same measurements for the sodium glass do not. This observation supports the hypothesis that glasses capable of homogeneous nucleation are structurally more similar to the resulting crystalline phases than those glasses that exhibit only heterogeneous nucleation.

Correlation of network structure with devitrification mechanism in lithium and sodium diborate glasses

“…[9]) and in lithium and sodium diborate (Li 2 O·2B 2 O 3 and Na 2 O·2B 2 O 3 , submitted for publication). In these studies we compared both cation-cation and cation-glass-former (silicon or boron) distance distributions between the glass and the final crystal phases.…”

Effect of the alkali concentration on the crystallization of BaF2 from Na2O/K2O/BaF2/Al2O3/SiO2 glasses

“…Here, the crystal phase precipitated has the same chemical composition as the glass [1,2]. In such systems, during the course of the crystallization, the chemical composition of the glassy phase does not change and the crystal growth velocity is constant during the entire crystallization process.…”

The effect of niobium- and tantalum oxide on nucleation and growth kinetics in lithium disilicate glasses

“…surface or bulk crystallization, and the structural similarity between glass and crystal [45e47]. From nuclear magnetic resonance spectroscopy, it was deduced that glasses showing homogeneous nucleation are structurally more similar to the crystal phase than glasses nucleating heterogeneously [48,49]. Longstaffe et al [48] analyzed stoichiometric lithium disilicate glass and the isochemical crystal phase and determined that both are structurally very similar at the intermediate-range level.…”