We report on a study of ultramarine pigments via Colorimetry, resonance Raman, and 27Al, 29Si solid-state NMR spectroscopy. NMR parameters are shown to correlate well with the intensities of Raman signals corresponding to the chromophores S 3 -. and S 2 -.. Further, a correlation is established between the colorimetric parameters L* (lightness) and C* (chromaticity) and the paramagnetic shift in NMR spectra for both 27Al and 29Si. The parameter h (hue) appeared not to vary over the range of paramagnetic host concentrations studied. Preliminary results on faded pigments in both acidic and basic media show that the concentration of diamagnetic guest molecules in the sodalite lattice rises, and some of the paramagnetic species are replaced.
|Number of pages||8|
|Journal||Materials Research Society Symposium Proceedings|
|State||Published - 19 Dec 2005|
|Event||2004 Materials Research Society Fall Meeting - Boston, MA, United States|
Duration: 30 Nov 2004 → 3 Dec 2004