“…In glasses or ceramics as sensing materials, the variation of their electrical properties, such as impedance or capacitance, is exploited for gas detection. There are, however, few papers dealing with glass ceramics as humidity [9] and gas sensors [10,11,12,13,14,15,16]. Thus, based on previous experiences [17,18], in this research, ZnO crystals were grown from a glassy matrix having the composition 58ZnO:4WO 3 :4Bi2O3:33.3B 2 O 3 by means of a crystallization process.…”