Abstract: Methods of making a strengthened ultra-thin glass substrate may include forming a film including a volume expanding composition on a glass substrate, and treating the film under conditions sufficient to cause volume expansion of the volume expanding composition, thereby generating internal compressive stress in the film such that compressive stress is imparted onto the substrate and a fracture strength of the substrate is improved. In some embodiments, the volume expanding compound is converted into a different compound with a larger volume When it is treated under sufficient conditions.