In this study, the effect of Ti 4+ on the structure of nepheline glass (NaAlSiO 4) is investigated as SiO 2 is systematically replaced with TiO 2. Traditionally, TiO 2 is considered to be a nucleating agent for silicate crystallization but can also be incorporated into the glass network in relatively large amounts as either a glass former or modifier depending on its coordination with oxygen. To determine the effect of Ti 4+ on the structure of nepheline glass, X-ray and neutron pair distribution function (PDF) analysis paired with Empirical Potential Structure Refinement (EPSR) were conducted and are supplemented with Raman spectroscopy and Ti Kedge X-ray absorption spectroscopy (including Extended X-ray Absorption Fine Structure, EXAFS). Through these methods, it has been found that up to 15 mol% (16 wt%) TiO 2 can incorporate into the glass network as a primarily four-fold coordinated species, with a minor contribution of five-fold coordinated Ti as the TiO 2 content is increased. Between NaAlTi 0.1 Si 0.9 O 4 and NaAlTi 0.2 Si 0.8 O 4 , EXAFS suggests a local structure change in the second nearest neighbor, from a Ti atom to an Al atom. Raman spectroscopy also suggests that as Ti content increases, the Na environment becomes more ordered.

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