An electrochromic structure can include a substrate and an electrochromic residue disposed on the substrate. The electrochromic structure can include an electrochromic stack on the substrate. A process can be used to separate the structure. The process can include forming a filament in the substrate and applying a thermal treatment to the substrate. Forming a filament can be performed by applying a pulse of laser energy to the substrate. In a particular embodiment, a filament pattern including a plurality of filaments can be formed in the substrate. The substrate can include mineral glass, sapphire, aluminum oxynitride, spinel, or a transparent polymer.