Reduction of thin electrodeposited films of α-PbO2 in aqueous sodium tetraborate results in the nucleation and growth of highly resistive PbO. Transmission and photocurrent spectroscopy as well as impedance measurements have been used to follow the reduction process, and the optical and solid-state properties of the system have been derived. No evidence for the formation of non-stoichiometric oxides such as Pb12O19 was obtained, and the results could be explained by assuming that the only phases present throughout reduction were a defective form of tetragonal PbO and α-PbO2.