Formation characteristics of glasses in the system AlF3 - MF2 -Ba(PO3)(2)(M=Ca, Mg, Sr, Ba) have been studied as a function of Ba(PO3)(2) content. Glass formation tendency increased with increasing Ba(PO3)(2). The critical cooling rate, R-c, for glass formation decreased from Rc 98 +/- 7 to 2 +/- 0.5 degrees C s(-1) when the Ba(PO3)(2) content of the glass increased from 0 to 1.5 mol%. The improvement in glass formation caused by Ba(PO3)(2) was due to linking of the broken chains present in the structure. The infrared transmission spectra of these glasses and their crystallization products suggested that the structure changed from short chains of AlF6 groups to long chains of PO3F and Ba(Ca, Mg, Sr)P2O7 groups with increasing Ba(PO3)(2) content of the glass.