This paper presents and assesses a thermal spraying process for applying electrically insulating layers on glass ceramic substrates. It reviews the crystal structure of glass and glass ceramic and explains how it influences splat morphology, phase transformation, and the properties of plasma-sprayed materials. It is observed that substrate preheating is necessary with glass ceramics as is substrate cooling; the former to promote adhesion, the latter to control residual stress. Spray parameters such as plasma power and powder feed rate also have an effect on residual stress and must be controlled as well. Paper includes a German-language abstract.