Sulfur speciation and network structural changes in sodium silicate glasses: Constraints from NMR and Raman spectroscopy

Modelling the sulfate capacity of simulated radioactive waste borosilicate glasses

“…The absence of Raman bands related to S-S bonds, S(IV) or S(V) complexes, which provide broad bands in the region 300 -460 cm -1 [72,73] supports this. Further literature support for this conclusion is provided by X-Ray absorption spectroscopy for other sulfate-doped radioactive waste borosilicate glasses prepared under oxidising conditions [73] and from redox potentials [74], which show that lower sulfur oxidation states are not formed in glasses produced under oxidising conditions.…”

Mechanical properties of soda–lime–silica glasses with varying alkaline earth contents

“…The feature at 990 cm 1 is believed to be related to dissolved sulphur which will originate from the Na2SO4 used for fining 25 , although no sulphur was detected in most of the XRF test results for the glasses produced here. However, Na2SO4 was not added to the M7C10S68 batch and this shoulder did not appear in the spectra of M7C10S68 supporting the assignment of this band to dissolved sulphur.…”

“…Due to the complexities of quantification of Q 4 (Si) and Q 4 (Al) species in this spectral range 25 detailed Q species quantification has therefore not been undertaken here. Instead the Raman polymerization index which is given by the ratio of the intensity of region C to that of the region A has been used to gain insight into the degree of polymerization, with a higher value of this index indicating a greater degree of connectivity 26,27 .…”

Dissolution mechanisms of water in depolymerized silicate melts: Constraints from 1H and 29Si NMR spectroscopy and ab initio calculations

“…Even the spectrum for the anhydrous glass cannot be uniquely deconvoluted without constraints. We have compared 29 Si MAS NMR spectra for anhydrous sodium silicate glasses with a range of silica contents from Na 2 Si 4 O 9 and Na 2 Si 3 O 7 , to Na 4 Si 3 O 8 compositions, for which peaks due to different Q n species are better resolved (see Tsujimura et al, 2004). The FWHM for a given Q n species do not show appreciable variations with silica content, whereas their chemical shifts move systematically to less negative values with decreasing silica content.…”