Transparent glasses based on a stoichiometric boron-containing sodium fluorphlogopite composition were prepared. Additions of boron in glasses lower the melting temperature and strongly affect the nucleation and crystallization temperatures. The crystallization process was studied by means of DTA, XRD, and SEM. Thermal treatment of glasses at 800 deg C for 5 or 20h did not show any crystallization of sodium fluorphlogopite, whereas at 500 degC/2h and 750 degC/2h crystallisation of sodium fluorphlogopite took place. Increase of crystal growth rate was observed in the microstructure with the increase of boron oxide in the glass-ceramic samples. The incorporation of boron oxide changed the infrared spectra of the parent glasses and the corresponding glass-ceramics and bands referred to triangular (BO3) and tetrahedral (BO4) groups were observed.
