Following recent advances in nucleation theory, there is renewed interest in comparing quantitative experimental nucleation data in glasses with theoretical predictions. Most work has been concentrated to date on relatively simple oxide compositions with few investigations of more simple multi component systems. 28 glass compositions were melted. Homogeneous glasses were cast as rods, allowed to cool in air and not annealed. Samples were given a nucleation heat treatment for different times followed by a growth treatment at a higher temperature. Polished sections were examined by reflection optical microscopy. Crystal growth rates were determined from single isothermal treatments, measuring either surface layers or volume nucleated crystals, the two methods giving good agreement.
