Soda-lime-silica glasses represent 90% of the world-wide glass production and their manufacturing is marked by the optimization of the glass melting process with respect to energy saving, waste gas cleaning and process automation. The objective of these optimizations is the improvement of glass quality. The impact of the oxidation state is reviewed on glass melt properties which are relevant for the melting and the forming process as well as for the final glass product. The employment of electrochemical measurements (oxygen activity and voltammetric sensors) allows a continuous in situ characterization and control of the redox state in glass melts and thus represents an efficient measure to improve glass quality.