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The process of glass solidification is analyzed in the context of the fundamental principles of physicochemical kinetics. The concept of the emergence of "solidification seeds", formation of "solidification layers" and their migration into the glass volume are discussed. It is demonstrated that the level of diathermancy of tinted glasses can characterize the force of the interaction between the colorant complexes and the main silicon-oxygen elements in glass and, consequently, can influence viscosity variation in solidifying. The proposed theoretical principles agree well with experimental and industrial data.The critical factor in molding glass articles is the glass solidification rate, which depends on the combination of viscosity variation depending on temperature and temperature variation in time. As a rule, published works on the kinetics of glass solidification describe qualitative results of experiments related to different diathermancy of glasses determined by introduction of colorants [1]. The new concept of glass solidification is based on fundamental principles of physics and chemistry of melts and solids, taking into account the vitreous state and the factors of surface and volumetric interactions in glass technology processes [2].Cooling and solidification of a highly viscous glass melt in the formation of glass articles proceed due to a complex heat exchange with the ambient medium with participation of thermal conductance and radiation. One should bear in mind the following specifics of industrial glass molding:-highly viscous glass melt delivered for molding is not totally homogeneous chemically, thermally, and optically; -cooling of glass melt is nonuniform; this is especially true of processes involving molds where a highly viscous glass melt contacts a heat-removing surface at a limited number of points;-cooling and solidification of glass melt starts from the surface and extends into the glass volume;.Taking into account the above specifics of glass melt cooling, it can be assumed that viscosity variations are likely to be fragmentary, both on the surface (fast process) and inside the volume (slow process).The results of the study in [3] demonstrated that a granular structure is registered in glass in forming, with a "grain" size of 4 -8 mm, parallel to the mold surfaces. The crosssection of molded articles (perpendicular to the mold surfaces) has a laminar structure with layer thickness of 2 -4 mm. Thus, the glass solidification process in molding can be represented in two stages:-emergence of "solidification seeds" (local areas of glass with increased viscosity) and the formation of a "solidification layer"; -expansion of the "solidification layer" into the volume of glass.The formation of "solidification seeds" is governed by probabilistic processes; the theoretical principles of these processes are formulated in the works of A. N. Kolmogorov (1937), M. Avramy (1939), and B. V. Erofeev (1950. According to the basic principles of these studies, the solidification rate (viscosity variation w...

A large number of publications addressing the solidification of glass in molding has been systematized. Different aspects of the effect of the basic composition of glass, diathermancy, time and structural factors on solidification processes are discussed. The workability of glasses and the main conditions for mechanized formation of glass articles are considered as well.The rate of solidification of glass is a critical factor in molding glass articles, which is characterized by viscosity variation with time and can be represented by the following equation:where h is viscosity; t is temperature; and t is time.It can be seen that the solidification rate is determined by viscosity variation depending on temperature and temperature variation with time. Viscosity variation depending on temperature, in turn, is related to the chemical composition of glass, whereas temperature variation with time is related to the cooling conditions. Thus, the rate of solidification of glass depends on the glass composition and the cooling conditions. Below we will consider factors responsible for the rate of solidification of glass, the working characteristics of glass, and the conditions of mechanized formation of glass articles. Main research trends and results will be discussed. More detailed data on the specified published sources, including the earlier ones, is contained in reviews [1 -6].The effect of glass composition on the solidification rate can be split into two directions: the effect of the initial composition and the effect of small colorant additives.The effect of the main composition of glass on the rate of solidification is caused by the impact of individual oxides on glass viscosity. Numerous studies systematized in publications [2, 3] consider the effect of various oxides on glass viscosity and its measurement methods. The identity of the effect of oxides of the basic glass composition on viscosity and solidification rate is also corroborated by certain special studies. Figure 1 gives generalized viscosity variation curves of "long-term" and "short-term" glasses in solidifying.The second direction is related to the effect of pigments on absorption in the IR spectrum range, which has an immediate effect on the rate and uniformity of solidification of tinted glasses. In estimating absorption in the IR spectrum range one usually applies the term "diathermancy." This characteristic of glass is essential for the processes of glass melting and formation of glass articles.Diathermancy of glasses. Systematic research on radiation and absorption in glasses at high temperatures was started by V. M. Dobiash and N. M. Litvinov (1930) and V. Éitel' and V. Lange (1931). The studies of V. Éitel' and V. Lange demonstrated that clear glass has the lowest radiating capacity, whereas colorants introduced into glass to a different extent increase its radiation capacity.The light transmission of clear and tinted glasses in a temperature range of 2 -600°C was investigated in the stu-

Dependences are identified that characterize redox reactions in the production of amber and brown glasses from batches using sodium sulfate with an excessive reducing agent or blast furnace slag. All reactions and resulting color shades are related to partial oxygen pressure. Boundary values for producing steady amber glasses are identified. The reducing potential of batches found by the oxydimetry method can be expressed via partial oxygen pressure, and it is recommended to determine this potential for tinted and clear glasses.