• Screiber, Henry D.
• Colomban, Philippe

Abstract

Composite materials formed by metal nanoclusters embedded in glasses/glazes have been produced for centuries (Roman hematinum and Renaissance alassonti, Coptic lustre-painted glass and Islamic lustre ceramics). Comparisons were drawn from Raman analyses of alkali borosilicate glasses coloured by copper as “blue” Cu2+ (peak absorption at 750 nm), as “colourless” Cu+, and as “opaque red” Cu0 (peak absorptions at ~420 and 570 nm). In particular, Raman analyses of copper-ruby glasses containing Cu0 nanocrystals were performed under blue (488 nm), green (514.5 and 532 nm), and red (647.1 nm) excitations, providing information on the glass structure around the Cu0 precipitate. Addition of europium to Cu0-containing glass melts yielded glasses that were dichroic; for example, a glass with 0.2 wt% Cu and 0.4 wt% Eu was red in absorbed light and blue in transmitted light. The backscattering Raman signature of the glassy silicate matrix containing copper indicated a less-polymerized network around the Cu0 nanocrystals/atoms than around Cu2+ or Cu+ (Raman index of polymerisation ~1 instead of ~2). Strong Rayleigh scattering is measured under blue excitation for all copper-containing glasses and under red excitation for Cu0-containing (red) glass.

Topics

• nanoparticle
• impedance spectroscopy
• melt
• glass
• glass
• laser emission spectroscopy
• composite
• copper
• precipitate
• ceramic
• Europium