Abstract: A glass furnace including a refractory portion defining a hot face in contact or intended to be in contact with molten glass or with a gaseous environment in contact with molten glass, and a cold face at a distance from the hot face, and a temperature measurement device. The temperature measurement device including a waveguide that includes a measurement portion including at least one temperature measurement sensor configured to send a response signal in response to the injection of an interrogation signal into the waveguide. The temperature measurement device including an interrogator connected to an input of the waveguide and configured to inject the interrogation signal into the input, to receive the response signal returned by the sensor in response to the injection of the interrogation signal, to analyze the response signal received and to transmit a message according to the analysis.