Glasses with composition 60B2O3–(40–x)MnO2–xNa2O (where x = 0, 5, 10, 15 and 20 mol. %) have been prepared using the melt quench technique. The structural analysis of glasses is carried out by X-ray diffraction, density, IR spectroscopy and thermal analysis measurements. The XRD profiles confirmed their glassy nature and FTIR spectra indicate that inclusion of modifier oxide produces BO3 and BO4 structural units by breaking the boroxol B3O6 ring. The glass transition temperature (Tg), crystallization temperature (Tc) and melting temperature (Tm) of the glasses decreases with increases of Na2O content in the system. Scanning electron microscopy study was also carried out with a view to throwing more light on their morphology aspects.