Recently it has been shown that the incorporation of AℓPO4 in a Zn2SiO4 phosphor results in an improved cathodoluminescent efficiency1. We report here on electron trap distributions in the substituted phosphors derived from UV excited thermoluminescent glow curve measurements. It has been found that the glow curve peaks are modified appreciably with AℓPO4 addition, but new peaks do not appear to be introduced. This shift, however is largely due to a considerable change in the absolute value of the detrapping rate, while there is only a relatively small change in the activation energies for detrapping. The phosphors were prepared in a silica rich environment and for the present study were not subjected to post preparation annealing treatments. © 1981 The Metallurgical of Society of AIME.