Strontium sulfide doped with europium and samarium is an infrared stimulable phosphor that is being investigated as the active thin film layer of a photonic data storage disk. Lithium and fluorine can be added to the SrS:(Eu,Sm) to fully activate the photonic properties of the material, and care must be taken to ensure sufficient crystallite size, minimize structural defects within crystal grains, and maintain a uniform chemistry throughout the film thickness. In this article we present the initial stages of a study of the relationship of these properties to film performance. A number of techniques are employed including x-ray diffraction, electron probe x-ray microanalysis, transmission electron microscopy, and secondary ion mass spectrometry. Initial findings provide information on the effect of structural defects on film performance, and the importance of the mismatch in thermal coefficient of expansion between film and substrate.