is then rf sputtered by conventional means on the silver chloride layer the temperature coefficient of the silver chloride and ph glass layer are matched whereby the ph glass will not produce microscopic cracks as during normal temperature cycling e g 0 u00b0 to 100 u00b0 c as in the case of outer glass layer used in the reference electrode previously described for example corning 1990 glass has a coefficient of thermal expansion approximately one half that of silver chloride other ph sensitive glasses can be produced to even more closely match the coefficient of thermal expansion of the silver chloride layer by using glass formulas with the following characteristics a high coefficient of expansion can be achieved by using oxides such as li 2 o na 2 o k 2 o rb 2 o cs 2 o bao and sro while a low coefficient of expansion can be achieved by using sio 2 b 2 o 3 al 2 o 3 beo and tio 2 thus the coefficient of thermal expansion of the silver chloride layer or other solid state electrolyte materials such as cuo agi rbi rbag 4 i 5 etc can be matched to an even closer approximation if either the temperature cycling during the measurement operation or the electrolyte material layer imposes a need for such a match the thickness of the ph glass is approximately 10 to 10k a a thermal compensator structure may be produced using an insulating substrate with a thermal sensitive element mounted therein and having the same overall.