The desorption of H and F from the surface of porous material, during annealing, was investigated by means of electron-nuclear double resonance; using the surface dangling bond electron paramagnetic resonance signal as a monitor. It was found that the line-width and anisotropy of the H-related signals decreased upon increasing the annealing temperature up to 700C. The F-related signal vanished above 500C. This behavior was in qualitative agreement with H desorption data which had been obtained by means of mass spectroscopy.

D.M.Hofmann, B.K.Meyer, P.Christmann, T.Wimbauer, W.Stadler, A.Nikolov, A.Scharmann, A.Hofstätter: Materials Science Forum, 1995, 196-201, 1673-8