The glass formation regions for B2O3-CoO-MnOm systems (MnOm+ZnO, PbO, Bi2O3
) have been determined via pouring the melts on a metal plate. An increase
in the glass formation region was achieved with the help of the roller tech
nique. it has been established by infrared spectroscopy that isolated BO3 a
nd BO4 groups together with pyroborate groups are formed in the structure o
f the boundary glass forming compositions.