The purpose of this work is to measure the amount of H2O which is bound tightly in spin‐on‐glass (SOG) and the amount of reabsorption as a function of room air exposure time. Both results are needed in determining bake cycles and wait times prior to metal deposition when SOG is used in the dielectric stack of a multilevel metal system. About a tenth of the amount of gas which remains after a 2 h 150 °C bake is still present after a 2 h 350 °C bake. About half the amount of the tightly bound gas which is desorbed will be reabsorbed upon exposure to air in a period of 4 h or less. The time for half of the reabsorption to occur appears to be of the order of 20 to 60 min.