Abstract: A normal pH sensitive glass electrode is deactivated by exposure to thermal treatments at relatively high temperatures of approximately 190.degree. C. for predetermined periods of time until the nominal electrode sensitivity is reduced to very low levels such that the output potentials of such deactivated glass electrode approach the characteristics desired for a theoretically perfect reference electrode.Additionally, a method of forming a deactivated pH glass electrode including the steps of exposing a normal pH or other ion sensitive glass electrode to high temperatures in the order of 190.degree. C. or higher for predetermined periods of time is disclosed.