The diffusion of H into Czochralski-type material led to enhanced O diffusion jumps in surface regions; as reflected by a relaxation of the stress-induced dichroism of the 9000nm band. It appeared that a sharp interface existed up to the point where dichroism was lost, and this implied that H diffusion was the rate-limiting step in the enhancement process at 225 to 350C. It was found that the H diffusion data could be described by:

D (cm2/s) = 1.7 x 102 exp[-1.2(eV)/kT]

R.C.Newman, J.H.Tucker, S.A.McQuaid: Materials Science Forum, 1992, 83-87, 87-92