Although the comparison of crystallinity grade by means of
comparison of Raman behavior of four investigated types of electrodes
would possibly allow better understanding of the differences
in the sensitivity of potentiometric pH determination by
means of W/WO3 electrodes established later on (Section 3.2.2),
it was not possible to obtain reliable Raman spectra of all the studied
electrodes using conventional Raman technique. Hence, this
question remains opened at this point