The diffusion of F in silica at 1385 to 1873K was deduced from concentration profiles which had been measured using scanning electron microscopy of plasma-activated chemical vapour deposited samples. It was found that the data could be described by:

log[D(cm2/s)] = -0.920 – 18337/T

The F diffusivity was much lower than that of Cl in silica, and the activation energy was higher: 351 rather than 212kJ/mol. It was suggested that this indicated the existence of different forms of binding of F and Cl in the silica network.

W.Hermann, A.Raith, H.Rau: Berichte der Bunsengesellschaft für Physikalische Chemie, 1987, 91[1], 56-8