Effect of boron on the water speciation in (alumino)silicate melts and glasses

Water- and boron speciation in hydrous soda–lime–borate glasses

“…These findings are consistent with studies on borosilicate glasses in which OH-groups are increasingly stabilized with increasing boron content [39,40]. But in contrast to borate glasses a larger fraction of molecular water species is present at higher water contents.…”

“…The NIR spectra of the borate glasses show similar features as hydrous boron containing silicate glasses reported in the studies of Romano et al [40] and Schmidt et al [39]. In the latter study a shoulder at~4650 cm −1 on the high frequency wing of the main OH combination band in the system NaAlSi 3 O 8 -B 2 O 3 -H 2 O was assigned to B III -OH.…”

“…Hydrous glasses of the join NaAlSi 3 O 8 -NaBSi 3 O 8 show a peak at 4750 cm −1 which was attributed to B IV -OH since 11 B-NMR spectroscopy points to the dominance of tetrahedral boron in these glasses [39]. In our soda-lime-borate glasses a shoulder of the main OH combination peak is developing with increasing network modifier content (from NCB5 to NCB25) at same wavenumber (Fig.…”

“…Analog to silicate glasses [19], the band at 4100 cm −1 is attributed to the combination of OH stretching vibrations with a low frequent lattice vibration. Absorption bands near 4600 cm −1 and at 5200 cm −1 are assigned to the combination of stretching and bending vibration modes of terminal OH-groups and of molecular water, respectively [17][18][19][20]39,40].…”

“…9. Data for the silicates [48], aluminosilicates [22,[49][50][51][52][53][54] and for borosilicates [39] are shown for comparison. In the study of Behrens and Yamashita [48] the higher values for the silicates in comparison to aluminosilicates were related to the effect of NBOs which promote the stabilization of OH-groups.…”