Analysis of relaxation on polypropyleneglycols above vitrification temperature

Relaxation processes of the structural rearrangement of clusters in liquids: 1,2-ethanediol, 1,2-propanediol, and 1,2,6-hexanetriol

“…when the parameters of the DH and DC (β DC , τ DCe ) equations are related as m DH = 1, 1 − n DH = β DC , ω DHe = 1/τ DCe [16,18]. As a result of combining our data on DRS with those available in the literature, the temperature ranges were extended to the glass transition region: 161-453 K for ED [7,8], 175-423 K for PD [9,22], and 238-423 K for HT [6]. The ε s , τ DHe , n DH , ε ∞DH , and (ε s − ε ∞DH ) values were determined by the least squares method using the Brent minimization algorithm.…”

“…In our previous works on the dielectric spectra of 1,2-ethanediol (ED) [7,8], 1,2-propanediol (PD) [9,22], and 1,2,6hexanetriol (HT) [6], we have drawn on the data on the microwave spectra (MS) and calorimetry to determine the parameters of the DH model required for calculating μ c . This work solved two problems.…”

“…First, the comparison of DRS of ED, PD, and HT made it possible to track the dependence of the macro-and microscopic properties of polybasic alcohols on the number of hydroxyl OH groups and the hydrocarbon radical lenhth. Second, by the example of these substances, the possibility of choosing the required parameters within the DH model itself was considered, which we partially described in [9,22].…”

“…The experimental data on the dispersion ε(ω) of ED [7,8], PD [9,22], and HT [6] we have previously analyzed using the DH equation DH …”

“…The glass transition temperatures T g (HT) measured by the calorimetric method are 206.4± In the present work (unlike [6,8]), when calculating the mean statistical squares of the cluster dipole moments 2 c 〈μ 〉 , the circular vibration frequencies of the molecule in the clusters ζ were calculated using the parameters new DH B (Table 1) rather than through the moments of inertia of molecules. These parameters were determined within the DH model for the relaxation time of the overall cooperative process τ DHth [11][12][13][14][15] by the technique described in [9,22], using the equation…”