It is the aim of this report to show experimental evidence for the compensation effect during water desorption from siloxane-based spin-on dielectrics. A single linear relationship was obtained between the activation entropy Delta S-# and the activation enthalpy Delta H-# for the elementary water desorption components in the degassing spectra for siloxane-based dielectric thin films. From this observation, an isokinetic temperature was derived at which all desorption rates become equal. It is argued that this temperature can be considered as a fundamental materials characteristic, governing the thermal stability of the dielectric thin film.