Photoluminescence (PL) with short N-2-laser pulses is a plied for in situ monitoring of electrochemical processes at the (100) p-Si/aqueous NH4F electrolyte interface during anodic oxidation followed by electrochemical hydrogenation at low cathodic potential. The anodic oxidation is carried out in a potential regime where electropolishing with current oscillations occurs. The etch rate of the anodic oxide, which is characterized by the reciprocal oscillation period(10) is changed by the composition of the fluoride solution. At the minimum of the current oscillations the PL intensity increases with decreasing etch rate and anticorrelates with the oxidation rate, which is monitored by the current. The hydrogenation of the Si surface is characterized by the anodic current transient. The PL intensity increases strongly during the decay of this transient.