The project deals with an experimental study of nucleation/glass stability as affected by chemical diffusion in sililicate glasses and glass.ceramics. The primary emphasis of the study is to characterize the mechanism(s) and kinetics of oxidation/reduction in iron.bearing silicate glasses and the effect of the valence state of iron on glass stability and crystalline nucleation. The results of this research should suggest novel approaches to the preparation of glass.ceramic materials through `controlled oxidation', i.e., the application/manipulation of a chemical potential gradient of oxygen to drive chemical diffusion and consequent structural rearrangement and crystalline nucleation in the glass. Controlled oxidation should additionally affect the equilibrium texture in the glass.plus.crystalline system; the ability to control this texture, and therefore control certain physical properties of the glass.ceramic. The oxidation/reduction studies will include glasses of basaltic composition (both fabricated and natural) in an attempt to characterize the effect of redox conditions on the kinetics of chemical diffusion and crystalline nucleation in mafic magmas.
