## 5 Discussion
The relationship between these quantities is expressed by the glass transition equation: \(q\tau_{g}=\delta T_{g}\), where \(\tau_{g}\) is the relaxation time at \(T=T_{g}\), and is the temperature range. In the model of delocalized atoms developed by [PERSON] [8], it is considered that atom delocalization, which is an ultimate displacement of an active atom, is a necessary condition for an elementary event in the process of viscous flow of glasses and melts. For this reason, as a result of the freezing of the atom delocalization process in the glass transition region, viscous flow effectively stops at \(T_{g}\), and the melt vitrifies, e.g., passes into a glassy state. This occurs when the energy of thermal vibrations of the disordered lattice per atom becomes equal to or lower than the atom delocalization enthalpy, which provides a certain glass transition criterion [11]. It was shown that the analysis of the viscosity equations allows numerical estimations of \(\delta T_{g}\)[8, 17]. Moreover, it shall be noted that these are not limited to only WLF or VFT models [5, 9, 20]. The dependence of the glass transition equation parameter \(\delta T_{g}\) on the glass transition temperature \(T_{g}\) in Equation (15) is due to a small spread in the fraction of the fluctuation volume \(f_{g}\). Such a dependence can also be obtained from several other considerations. If the equation for the so-called fragility of glass-forming melts, which is determined by the temperature dependence of the viscosity of the liquid \(\eta(T)\) near the glass transition temperature [49]  
\[m=\left.\frac{d\ln\eta(T)}{d\left(T_{g}/T\right)}\right|_{T=T_{g}} \tag{18}\]  
substitute the temperature dependence of viscosity from the WLF Equation (3); then, this will lead to the expression:  
\[m=\left(\frac{C_{1}}{C_{2}}\right)T_{g}. \tag{19}\]  
Considering expression (12) at \(m\approx const\), a linear correlation follows between the temperature interval \(\delta T_{g}\) and the glass transition temperature \(T_{g}\):  
\[\delta T_{g}=\left(\frac{1}{m}\right)T_{g}. \tag{20}\]  
The fragility \(m\) serves as a characteristic of glass classification [50]. Hence, we can conclude that this linear correlation is valid for glasses of the same class with an almost constant fragility \(m\approx\) const. For example, silicate glasses with a network structure have a lower fragility m than glasses with a chain structure. For most glasses, the value of \(\delta T_{g}\), according to (15), at known values of \(f_{g}\) is no higher than 1% of the glass transition temperature. Thus, the narrowness of the temperature interval \(\delta T_{g}\) can be explained by the low value of the fraction of the fluctuation volume \(f_{g}\) frozen at the glass transition temperature, which agrees with the classical concept of a small temperature interval in which the liquid structure freezes. Although we currently do not have the necessary data for calculations, we note that empirical parameters of the WLF equation for polystyrene polymers could be of particular interest, as it was recently shown that the architecturally-different blends of these polymers could exhibit interesting surface transitions potentially affected by the liquid-glass transition related to the evident role played by the polymer topology in it [49, 51, 52].