Colour and chemical stability of bismuth oxide in dental materials with solutions used in routine clinical practice
Fig 7
FT-IR spectra for treated materials at 24 weeks after exposure.
Spectra for Dark and Light conditions were averaged for noise reduction, there being no detectable systematic difference between the two. Spectrum for Bi2O3 included for reference. Artefact marked ‘?’. Contribution from atmospheric CO2 incompletely cancelled. (a) H2O: oxide, with carbonate present. (b) NaOH: oxide still detected, but strong carbonate peaks found for added CO2. (c) NaCl: oxide remains, strong carbonate peaks for added CO2. (d) NaOCl: no oxide detectable, nor carbonate. Moderate broad peak with two satellites attributed to bismuthate. (e) HCl: only BiOCl detected. (f) Blanks: showing that KBr disc spectrum is clear after background subtraction except for the artefact at 419 cm-1 and unknown peaks at 1060 and 1205 cm-1.