Glasses in the system (PbO)(30)(P2O5)(40)(ZnO)(30-x)(Li2O)(x) (where x = 0, 15, 20, 25, 30 mol%) and (PbO)(30)(P2O5)(50)(ZnO)(20-x)(Li2O)(x) (where x = 0, 5, 10, 15, 20 mol%) were prepared by conventional melt quenching technique. XRD and DSC measurements were performed to confirm their amorphous nature. Thermal stability factor (S) has been evaluated using the values of T-g and T-c. The refractive indices of these glasses lie in the range of 1.40-1.45. IR spectra of these glasses show absorption peaks in the range 1233-1247 cm(-1), 1076-1087 cm(-1), 905-894 cm(-1), 735-731 cm(-1) and 531-556 cm(-1) corresponding to P=O, P-O-, (P-O-P)(AS), (P-O-P)(s) and O-P-O vibrations respectively. The peak corresponding to P=O, shows red shift with increasing Li2O content indicating depolymerization of phosphate network. (C) 2012 Elsevier B.V. All rights reserved.