Dear all,
After spending hours googling on the topic stated in the subject, I have a general idea of how it works. Could someone please double check whether I am right or not?
Hydrogen ions from the solution (i.e. external) bind to the static oxide ions that are firmly affixed onto the silica network. As it does, a complement amount of Hydrogen ions from the reference also bind to the opposite surface of the silica network. This very amount tells the electrode how much of Hydrogen ions are there outside, and therefore functions to indicate the pH.
*Hydrogen ions = Hydronium ions
Regards,
Bill