Photoinduced disproportionation of RU(bpy)(3)(2+) on porous Vycor glass occurs within a fixed array of reactants by means of a mobile, photodetached electron. The absence of emission quenching when Ru(bpy)(3)(2+) cation exchanges onto the glass and the band gap of SiO2, the principal constituent of the glass, preclude direct electron injection into a conduction band. Instead, conduction of the photodetached electron is thought to occur via surface conduction, where the photodetached electron populates intermediate surface acceptor sites. These are shallow energy wells from which the electron can be thermally activated, but the specific identity of the site is not presently known. One possibility is the B2O3 Lewis acid sites present in the glass, and data presented here show that selectively neutralizing these B2O3 sites with chemisorbed NH3 changes the quantum efficiency of disproportionation. The same chemistry is shown to occur in the presence or absence of chemisorbed NH3, but a surprising increase in the quantum efficiency of Ru(bpy)(3)(2+) disproportionation in the presence of chemisorbed NH3 indicates that the B2O3 Lewis acid sites are not involved in electron transport between the immobilized ions.