Nearly constant loss behavior of lithium disilicate during devitrification

Abstract The temperature and frequency dependence of the electrical conductivity has been measured in Li-disilicate glass as a function of its devitrification from the glassy to the fully crystallized state. We found that below ∼50 K the conductivity is dominated by the nearly constant loss (NCL) behavior at all stages of devitrification. The findings are confirmed by 7Li nuclear spin relaxation measurements. The magnitude of the conductivity is shown to decrease remarkably with increasing devitrification, indicating significantly different jellyfish configurations in the crystalline and glassy phases. The evolution of conductivity with devitrification time can be explained quantitatively by a simple two-phase, Johnson–Mehl–Avrami type model based on a linear superposition of the NCL contributions of the glassy and crystalline phases.