Abstract: Dielectric oxide materials prepared by producing a sol from a mixture of a metal oxide precursor, a solvent, and an epoxide, and preparing a metal oxide material from the sol. In various versions, the mixture can also include a cosolvent, one or more additional metal oxide precursors, water, or a precursor to a glassforming oxide, or any combination thereof. The prepared dielectric oxide materials can be in the form of thin films having high ? values, low electrical leakage, and low dielectric loss tangent values.