A structural investigation of (100-y)[50P2O5-15ZnO-(35−x)PbO-xCdO]-yAl2O3 polyphosphate glasses was carried out using Raman, NMR (31P, 207Pb and 27Al) and XPS spectroscopies. In alumina-free glasses (y=0), the CdO substitution for PbO induces a strengthening of the network formation, up to x=20. For x>20, the network connectivity decreases because less cations are located in network former sites. In aluminophosphate glasses (x=20 and
