Influence of glass polymerisation and oxidation on micro-Raman water analysis in alumino-silicate glasses (original) (raw)

2009, Geochimica Et Cosmochimica Acta

The development of an accurate analytical procedure for determination of dissolved water in complex alumino-silicate glasses via micro-Raman analysis requires the assessment of the spectra topology dependence on glass composition. We report here a detailed study of the respective influence of bulk composition, iron oxidation state and total water content on the absolute and relative intensities of the main Raman bands related to glass network vibrations (LF: ~490 cm −1 ; HF: ~960 cm −1 ) and total water stretching (H 2 O T : ~3550 cm −1 ) in natural glasses. The evolution of spectra topology was examined in (i) 33 anhydrous glasses produced by the re-melting of natural rock samples, which span a very large range of polymerisation degree (NBO/T from 0.00 to 1.16), (ii) 2 sets of synthetic anhydrous basaltic glasses with variable iron oxidation state (Fe 3+ /Fe T from 0.05 to 0.87), and (iii) 6 sets of natural hydrous glasses (C H2OT from 0.4 to 7.0 wt%) with NBO/T varying from 0.01 to 0.76.