Formation of copper nanocrystals in alkali-lime silica glass by means of different reducing agents

In this work, metallic tin, SiC and metallic zinc, were mixed with a copper containing alkali-lime-silica glass in order to investigate the precipitation process of colloidal copper-nanoparticles induced by external reducing agents. Metallic tin has been traditionally employed in copper reduction even by ancient glass makers, while SiC, although suggested from the literature, was not yet properly studied for this application. Moreover, metallic zinc was chosen on the basis of Ellingham’s diagrams and used for the first time for inducing copper reduction in glass. Samples with different reducing agent concentrations were prepared. The structural and optical properties of the samples were characterized by means of X-ray diffraction (XRD), UV-vis absorption and fluorescence spectroscopy. Moreover, the redox processes between the different reducing agents and cupric oxide were studied by means of differential scanning calorimetry (DSC).