Infrared emitting ZnO-Li2O-Na2O-P2O5 glasses with different concentrations of Nd2O3 were prepared by melt quench technique. The glasses were studied successfully by applying the Judd-Ofelt theory. Infrared to visible upconversion was due to excited state absorption (ESA) and energy transfer upconversion (ETU). The observed transitions are related to transitions 4G7/2 →4I9/2 (530 nm), 4G7/2 →4I11/2 (590 nm) and 4G7/2 →4I13/2 (687 nm).