The physicochemical processes occurring in glasses of the PbO–CdO–SiO2–B2O3–Al2O3 system after high-temperature contact with oxides of various metals—CuO, NiO, Al2O3, TiO2, Nb2O5, and WO3, as well as the electrical resistance of the obtained glasses—are studied by X-ray phase analysis, infrared spectroscopy, and electron paramagnetic resonance. It is established that these properties are determined by the acid-base and redox properties of the oxides and glasses, which directly depend on the content of the O2– ion in each specific composition.