Simha vitreous state

The S-S equation of state was derived for thermodynamic equilibrium conditions. In the vitreous state, the configurational thermodynamics depends on P, T, the way glass was prepared, and time thus, the occupied volume fraction y = 1 — A=y P, T, to), where U is the annealing time. Accordingly, McKinney and Simha [1974,1976] replaced the standard definition of pressure in Eq. (6.39) by the general function of... 

The simplified procedure starts with computation of the characteristic P, 1, V parameters from the PVT data at T> Tg. Next, from Eqs. (14.2) and (14.3), the fictitious hole fraction in the glassy state at T < Tg and P (a prime indicates an independent variable in the vitreous state) is calculated as /lextrapoi = ( P )-Subsequently, from the PVT data at T < Tg, using Eq. (14.2), the hole fraction in the glassy state, hgu = h(T, P ), is computed. Thus, for the same set of T, P, the hole fractions that the melt would have, /lextrapoi, and the factual one, /igiass > extrapoi, are determined. From the isobaric values of h versus T, the frozen fraction of free volume is calculated as [McKinney and Simha, 1974]... 

Solid body. In amorphous systems, calculate the hole fraction in the vitreous state, h = h P and then the pressure and composition dependencies of the frozen free-volume fraction, FF = FF(P, w). The semicrystalline systems must be treated as supercooled liquids (described by the S-S equation of state) comprising dispersed crystals, described by the Midha-Nanda-Simha-Jain equation of state [see Eqs. (6.32) to (6.34)]. 

The analysis of vitreous state data followed the simplified procedure, justified by earlier works [Quach and Simha, 1971, 1972 McKinney and Simha, 1974, 1976 Curro et al., 1981 Utracki, 2007a]. The independent variables in the glassy state are indicated by primes (i.e., T and P ). From the PVT dependencies the hole fl action, hg ass = h(T, P ), was calculated by substituting V=V T, P ) into Eq. (14.2), for which the P ), (7 ), and (V )parameters were known from the T> Tg data. The hole fraction that the melt would have at T and P, /lextrapoi = KT, P was computed from... 

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