Effect of pressure on thermally induced diffusivity and reactivity of water in thin amorphous silica films

Abstract

We have studied the effect of water pressure on the exchange phenomena between ¹⁸O-labelled water and thin thermal silica films. We have shown that the Doremus model applies; that is, water molecules diffuse in interstitial positions while exchanging their oxygens with those of the silica network. H₂O diffusivity is not affected by pressure variations, while reactivity seems to be. We discuss the latter point.