This disclosure provides systems, methods, and apparatus for tempering or chemically strengthening glass substrates having electrochromic devices fabricated thereon. In one aspect, an electrochromic device is fabricated on a glass substrate. The glass substrate is then tempered or chemically strengthened. The disclosed methods may reduce or prevent potential issues that the electrochromic device may experience during the tempering or the chemical strengthening processes, including the loss of charge carrying ions from the device, redistribution of charge carrying ions in the device, modification of the morphology of materials included in the device, modification of the oxidation state of materials included in the device, and the formation of an interfacial region between the electrochromic layer and the counter electrode layer of the device that impacts the performance of the device.