This book contains the proceedings of a workshop held at the Institute
Laue-Langevin in Grenoble in September 1988. Review articles and
contributed papers survey recent theoretical and experimental
developments on disordered materials and in particular on glasses. A
large part of the book concerns the recently proposed mode-coupling
approach to the behaviour of a viscous liquid around its glass
transition, where the relevant dynamics extend over a broad range in
time scales and the application of quite different experimental
techniques becomes essential. Contributions report on experiments using
dielectric relaxation, NMR or light scattering techniques, and
especially neutron scattering techniques. One signature of disordered
materials is the occurrence of an excess vibrational density of states
at low frequencies. Some situations are presented where the density of
states can be understood by taking into account the peculiarities of
intra- and intermolecular motions. Another approach to the dynamics of
disordered materials is the fracton picture, developed to describe the
excitations of fractal objects. Several contributions discuss the
dynamics of such fractals, studying mainly the vibrational density of
states, and some discuss the application of the fracton concept to
materials without a fractal structure like glasses.