1 University of Chemical Technology and Metallurgy, Sofia, Bulgaria;
2 Academy of Science, Institute of Electrochemistry and Energy systems, 1113 Sofia, Bulgaria
The ion-exchange process causes structural transformation and modification of the properties of the treated glasses as a result of interdiffusion of Na+↔M+ (M= Cu, Ag, Au). These changes are favoured by the disordered structure and the presence of non-bridging oxygen atoms in the multicomponent oxide glasses network. Float glasses with a composition 73SiO2.13Na2O.8CaO.4MgO.2Al2O3 (mol%) were subject to ion-exchange in two-component (CuSO4-Na2SO4; CuSO4-K2SO4) and ternary salt mixtures (CuSO4-ZnSO4-Na2SO4; CuSO4-ZnSO4-K2SO4). The presence of tin in the surface layer of float glasses in different oxidation form (Sn0, Sn2+, Sn4+) favours the formation of copper colloidal particles in the glass matrix, in result of which the glasses are colored in red or brown. Introduction of Zn ions to some rate in the composition of the melt prevents the reduction of the copper ions and the obtaining glasses are coloured either in yellow green or blue green, depending on the type of the predominant particles. Here we report the influence of experimental conditions (composition of the melt, temperature and processing time, additional treatment) on the size of colloidal nanoparticles, the optical characteristics and the achieving a variety of colour shades of the ion-exchange glasses. The optical properties of the nanostructured glasses were investigated by UV-VIS spectrophotometer. The presence of nanoparticles was revealed by their Surface Plasmon Resonance (SPR)-an absorption peak was observed at 560–650 nm. By XPS was provided information about the elemental composition and their chemical state. The crystal precipitating in the diffused layers were identified by X-ray diffraction (XRD). The morphology changes (shape and size of obtained nanoparticles) of ion exchange treated glasses were investigated by Scaning electron microscopy (SEM).