TABLE OF CONTENTS This section discusses the calculation scheme for estimation of the glass transition temperature T g developed in works [6, 128]. According to this scheme, the coefficients of molecular packing for polymers of various chemical structures are approximately equal at the glass transition temperature of each of polymers, this value k g being estimated by the value k g ? 0.667 for linear polymers. The coefficient of molecular packing k 0 near the absolute zero is also approximately equal for all polymers and is 0.731.
These measurements indicate that the transition from the glassy state to the rubbery state proceeds, when a definite part of empty volume is reached, equal f E = 1 - k g = 0.333, and expression for the glass transition temperature may be presented in the following form:
| (IV.39) |  |
It should be noted that the material discussed in the present Chapter is tightly connected with the material discussed in Chapter III. Using expressions for ? G deduced in Chapter III, it must be written down that
| (IV.40) |  |
where 
; Z is the coordination number of the i-th atom; D 0 i is the bond energy of the i-th atom with neighboring ones; ? V i is the Van-der-Waals volume increment of the i-th atom.
Numerical values of 1/ Z iD 0 i, typical of every atom and every type of intermolecular interaction,...
