The past, present, and future of the Johari–Goldstein relaxation

A short overview is given of the discovery of the Johari–Goldstein (JG) relaxation. The current perception that it plays an important role in the molecular processes leading to the alpha relaxation is due to K. L. Ngai and associates. Recently it has become apparent that the activation barriers for the JG relaxation are too high to be consistent with an intra-basin process, and the relaxation must involve an inter-basin one, contrary to the original view of Johari and this author.