Phase separation and the properties of lithium strontium silicate glasses

The immiscibility region covers most of the region of glass formation in the lithium strontium silicate system. Although the density, refractive index, and thermal expansion coefficient are insensitive to the presence of phase separation, the glass transformation temperature can be used to determine the limit of immiscibility in this system. The dilatometric softening temperature was used to determine the boundary the limit of connectivity of the silica-rich phase. The electrical conductivity and activation energy for conduction were used to determine the limit of connectivity of the lithium-rich phase.