Photoluminescence spectroscopy is used to analyze the effects of post-growth thermal annealing on the electronic properties and capture processes of self-assembled GaAs/AlGaAs quantum dots grown by modified droplet epitaxy. Post-growth annealing induces deep changes in the electronic structure of the quantum dots material, modifying both capture processes and photoluminescence quenching channels. The optical data, together with theoretical models, are used to quantify such structural and electronic modifications in the annealed materials. (C) 2002 Elsevier Science B.V. All rights reserved.