4. Conclusions glasses doped ons have been examined as a function of PbF2 concentration. Correlation between xRD, content and glass properties has been evidenced by DSC, absorption and luminescence spectroscopy. X-ray diffraction analysis indicates that glass samples containing small amount of PbF2 are fully amorphous in contrast to highly concentrated PbF2 doped samples, where GaPO4 crystalline phase was identified. It was also confirmed by DSC and absorption spectroscopy. Based on the bonding parameters and spectral widths of NIR luminescence bands we suggest that the degree of covalency between Er ions and the nearest surroundings increases with increasing PbF2 concentration in lead phosphate glass. Near-infrared luminescence spectra of Er3 ions and their decays are presented and discussed with PbF2 content. The luminescence lifetime of Er is 3/2 found to be maximum at 18 mol% of PbF2