Compositional changes of physical parameters associated with homogeneous crystal nucleation in silicate glasses are investigated. Dilatometric measurements and cylinder compression techniques are utilized in order to determine the reduced glass transition temperature, Trg, and the specific frozen-in birefringence, C, of several glasses of the (pseudo)-binary systems: lithium disilicate - sodium disilicate (LS2-NS2), lithium oxide - silica (L-S) and sodium oxide - silica (N-S). It is found that the log (lomax) - Trg curve reaches the lower detection limit for volume nucleation at Trg ~ 0.58. Homogeneous nucleation is indicated by a change of the optical anisotropy. The specific frozen-in birefringence decreases with decreasing reduced glass transition temperatures.
