The structure and radiative properties of aluminophosphate glasses in the system K2O-Al2O3-P2O5 and BaO-Al2O3-P2O5 were investigated. The structural changes in glasses with the addition of alumina were investigated by using FTIR spectroscopy and NMR spectroscopy. In the case of the K2O-Al2O3-P2O5 glasses, the aluminium atoms were mainly octahedrally coordinated and acted as network modifiers. The decrease in the spontaneous emission rate of K2O-Al2O3-P2O5 glasses was due to the tightening of chains in terms of the addition of alumina to the glasses. The increase in effective linewidth was probably due to the increase of end groups in the glasses. In the case of BaO-Al2O3-P2O5 glasses, the addition of alumina had little effect on the radiative properties, probably due to the small structural change which occurred on its addition.