Nucleation efficiency in lithia-alumina-silica glasses

The efficiency of TiO2 as a nucleating agent in the Li2O—Al2O3—SiO2 system is explored over a wide composition range. Sharp changes in crystal growth rate, which strongly influence nucleation rate, are observed near the Li2O·Al2O3—SiO2 composition line and are ascribed to changes in fluidity of the glass at the crystal growth front caused by rejection of lithia-rich material by the growing crystals. A mechanism for triggered nucleation at the growth front is advanced to explain a discrepancy between crystal growth rate and final particle size. The general implications of the results are briefly discussed.