Dielectric relaxation occurs in an enormously wide variety of systems in the gaseous, liquid and solid states. For the chemist, measurements of dielectric relaxation times are often of use for determining rate constants of chemical and electrochemical reactions in dielectric media, and also for investigating the structures of many liquids and solids. In this type of work, a detailed analysis is made of the molecular or ionic processes responsible for the observed delayed response to the applied field (usually, but not always, an electric field). The method of analysis varies a great deal according to the special nature of the process studied. Measurements of this kind can often also provide information of immediate practical interest--for example on the onset of insulation breakdown in cables to an electrical engineer-even though the mechanisms responsible for the effect are not known. The overall result is that work in this general area tends to be scattered between many groups, with few points of contact. One consequence is that the usefulness of dielectric relaxation measurements in a particular field may not be realized for some time. An example of this is the recent demonstration by Thirsk and co-workers (following earlier work of Frumkin) of the value of these measurements in studying reversible adsorption at the electrode/solution interface. A book attempting to present a concise general outline of the types of process which can be studied by relaxation techniques is therefore of general interest to chemists, and of particular interest to electrochemists.
Miss Daniel outlines the main applications of relaxation measurements in gases, liquids, crystalline, glassy, amorphous and hydrogen-bonded solids, and also in ferroelectric materials.
Her aim is to discuss these in terms of as simple a theoretical approach as possible. The theory is discussed in Chapters 1-9, which constitute the larger part of the book. There are inevitable disadvantages in attempting a general treatment in terms of simplified models. One is that proofs are usually only sketched, or not given at all. Equation 2.48 (p. 24), to take a random example, is an important one, but no proof (or explicit reference to one) is provided. Another disadvantage is that the treatment is almost entirely in terms of classical concepts, quantum considerations rarely being introduced. However, in a work of this size, these are outweighed by the usefulness of a clear and reasonably connected account of the field. A book of this scope has been needed for a long time.