Changes in the composition of metal-organic chemical vapor deposited, uncapped hafnium silicate films of various HfO2: SiO2 ratios, have been evaluated as a function of anneal temperature by Rutherford backscattering spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, x-ray diffraction, x-ray reflectivity, secondary ion mass spectroscopy, and high angle annular dark field scanning transmission electron microscopy with electron energy loss spectroscopy. The degree of phase segregation and the onset temperature of crystallization has been determined and the percent crystallization has been correlated with leakage current as a function of anneal temperature for each film composition. Fine structure x-ray spectroscopy has been utilized to evaluate the integrity of the interfacial oxide and the change in silicon concentration has been compared for each composition as a function of temperature. Trends associated with interfacial oxide growth, material intermixing, and phase segregation during anneal have been observed.