B3LYP periodic calculations with double-zeta polarised basis set using CRYSTAL06 code have been run on a bioactive phospho-silicate glass similar in composition to Bioglass (R) 45S5 (46.1 SiO2, 24.4 Na2O, 26.9 CaO and 2.6 P2O5 mol%) and a phosphorous-free soda-lime glass (49.5 SiO2, 24.2 Na2O and 26.4 CaO mol%). Initial structures have been obtained through a melt-quench process by classical molecular dynamics techniques and the effect of phosphorous on the glass network structure and dynamics have been assessed by B3LYP vibrational spectra. (C) 2009 Elsevier B. V. All rights reserved.