Brightness waveforms in electroluminescence

The shape of the "brightness waves" in electroluminescence depends on many factors: field intensity, frequency, and the direction in which the light output is observed. The shape also depends on the device used as electroluminescent condenser and, for some substances, the shape is slightly different according to the spectral region observed. In the Gudden and Pohl effect (momentary illumination) there is a similar appearance of the disturbances shown in electroluminescence. In the electro-extinctive effect the shape of the brightness waves changes quickly during the first second and then slowly for about ten seconds after the field is applied.