Alkali Ions in Network Oxide Glasses

4 DIFFUSION OF ALKALI IONS IN NETWORK OXIDE GLASSES 

Na+ ions are highly mobile compared to the glass-forming components and possess a diffusivity which follows Arrhenius behavior [21, 26, 29, 31, 33]. Furthermore, the activation energy for diffusion decreases markedly (and the diffusivity increases correspondingly) as the modifier concentration is increased, as in Fig. 10.8. The 

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