Characterization of optical coatings for artwork protection by means of neutron reflectometry

A multilayer coating on a glass pane, specifically designed for artwork protection, has been designed. The materials selected for the coating are SiO2 (silicon oxide), TiO2 (titanium oxide) and ITO (indium tin oxide). Prototype layers were deposited by thermal evaporation on glass substrates. Neutron reflectometry consists of measuring the amount of neutrons reflected by a specimen at angles close to total reflection and can be successfully used to evaluate thickness, surface and interfacial roughness, and material inhomogeneity of each layer in the coating. Neutron reflectometry has demonstrated that some layers are likely to be affected by inhomogeneity that should be controlled to optimize the final performance of the device.