Research on glassy semiconductors continues to expand every year. This is evidenced by the ever-increasing number of articles devoted to glassy semiconductors and published in a great variety of periodicals. The time has come to systematize and generalize the abundant published experimental material. The first review of the experimental data on glass formation and the physicochemical and physical properties of chalcogenide glassy semi- conductors was published by B. T. Kolorniets 1]. Glass formation in chalcogenide systems is the subject of a section in a monograph by Rawson 2]. In 1972 the...