FTIR spectroscopic structural studies of gel-derived glasses in BPO 4 -SiO 2 and BPO 4 (GaPO 4 )-SiO 2 systems are presented. 1 0 B isotope substitution, spectra subtraction procedure and B 3 + ->Ga 3 + substitution were applied to distinguish the bands, originating from B-O, P-O and Si-O bond vibrations. The spectra of borophosphosilicate glasses containing 1 0 B isotope have also been presented. Changes in the band positions helped to assign bands due to the different B-O bonds vibrations. The spectra subtraction procedure, due to the lowering of intensity of bands assigned to Si-O bonds vibrations, enabled to observe bands at 966 and 1225cm - 1 , due to broken Si-O - bridges and (PO 2 ) - terminal groups, respectively.