Glassy amorphous oxides are fascinating materials in that their amorphous nature provides for enormous functionality. In their thin film form, vapor deposited amorphous oxides are the building blocks of interference coatings ubiquitous in optical systems. In this talk I will describe the synthesis and characterization of amorphous oxides by ion beam sputtering. I will describe how it is possible to tailor the structural, optical and mechanical properties to realize thin films with ultra-low internal friction for interference coatings of gravitational wave detectors. The state-of-the-art of multilayer dielectric structures for this application and their future demands will be discussed.