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. (C) 2010 Elsevier B.V. All rights reserved.