## 5 Discussion  
The liquid-glass transition has a dual nature demonstrating both kinetic [36; 37; 38; 39] and thermodynamic phase transformation features [7; 38; 39; 40; 41; 42; 43]. Indeed, the higher the temperature of an amorphous material, either polymer or inorganic, including metallic systems, the more chemical bonds are broken in it. Broken bonds weaken the bond lattice of material, and because of that, the viscosity of amorphous materials is lower at higher temperatures, with typical molecular building blocks of the material becoming increasingly free to move. Hence, there is a gradual change of its solid-like behavior to a more gas-like type behavior which in the kinetic approach is agreed to occur when the viscosity is getting lower than a certain value, such as the generically agreed through Equation (1) \(\eta_{g}=10^{12}\) Pa-s. In the thermodynamic phase transformation approach, often labeled as configuron percolation theory (CPT) [5; 9; 11], the broken bonds in amorphous materials are termed configurons [6] and are analyzed as a separate phase [7; 40]. The glass-liquid transition is then described on the basis of the Kantor-Webman theorem, which states that the rigidity threshold of an elastic percolating network is identical to the percolation threshold [44]. The configuron phase up to the temperatures close to \(T_{g}\) is a point-like set, and the mathematical set theory characterizes it as a set with a Hausdorff dimensionality equal to nil. On the further increase in temperature of the glass, exactly at \(T_{g}\), the system of configurons forms for the first time a macroscopic percolation cluster. Accordingly to Kantor-Webman theorem, at this temperature and above it, the material is not anymore an elastic solid (glass), transforming into a liquid. The cluster made up of configurons is known to be a fractal characterized by the Hausdorff dimensionality 2.55 \(\pm\) 0.05 within set theory [45]. Thus, the set of configurons changes its dimensionality in a stepwise manner from 0 to 2.55 \(\pm\) 0.05 at \(T_{g}\), which can be interpreted as a kind of symmetry change characterizing the structural difference between glasses and a molten phase of matter [34; 40]. It is important that this approach (i.e., CPT) enables structurally to distinguish glasses from melts using experimental data of X-ray diffraction in amorphous materials [11; 34; 46; 47]. Thus, the account of configuron phase formation above the \(T_{g}\) (in the melt) shows that the glass-liquid transition within CPT is similar in nature to the second-order phase transformations following [PERSON]'s classification of phase transformations. From the point of view of the relaxation theory of glass transition, the liquid-glass transition process (vitrification) has a pronounced relaxation character and is subject to kinetic laws [4; 5]. During the cooling of the glass-forming liquid in the glass transition region, molecular rearrangements become slower, as a result of which the change in the structure does not have time to follow the decrease in temperature. An equation similar to the Bartenev Equation (8) has been successfully used not only for the liquid-glass transition process but also for other relaxation processes [29]. When the temperature changes at a constant rate q, the condition for observing a structural relaxation transition is written as \(q\tau_{i}=C\), where \(\tau_{i}\) is the relaxation time of the \(i\)-th relaxation process. As an example, thermal stimulation of the electrical depolarization of an amorphous polymer can be cited, which refers to structural relaxation, and the condition for its observation is described by a similar relation [48]. Within the framework of this approach, the relation between the structural relaxation time \(\tau\) and the melt cooling rate \(q=dT/dt\) plays a decisive role in the glass transition of a liquid.