Low-temperature equilibrium and nonequilibrium glass dynamics on a broad time and temperature scale investigated via optical hole-burning spectroscopy

The recent results in low-temperature relaxations of organic polymers and glasses, obtained in joint research of Bayreuth University and Institute of Spectroscopy RAS groups are reviewed. The comprehensive investigations of equilibrium and nonequilibrium spectral diffusion (SD) via optical hole-burning spectroscopy on a broad time (10(-5)-10(6) s) and temperature (0.1-4.2 K) scale are carried out on a few polymer and organic glass samples. Some new effects are discovered and interpreted, such as the nonlogarithmic long-time SD asymptotic; nonequilibrium SD, induced by an external electric field; light-induced SD, etc. The results of the investigations show that optical hole-burning spectroscopy is a very efficient technique for investigation of low- and intermediate-temperature organic glass dynamics. (C) 2000 Published by Elsevier Science B.V. All rights reserved.