A Comparative Study of Molecular Motion Cooperativity in Polymeric and Metallic Glass-Forming Liquids

Abstract

In order to investigate the relationship between the bonding nature and the cooperative relaxation, a comparative study of the relaxation behavior in polymeric and metallic glass forming systems has been performed based on the Bond Strength–Coordination Number Fluctuation (BSCNF) model developed by the authors. In the present work, we studied the correlations between the fragility m, the Vogel temperature T0, the degree of molecular cooperativity NB, and the Kohlrausch exponent βKWW. The results show that T0 and NB increase, whereas βKWW decreases systematically with the increase of m. Reflecting the difference of the interatomic interactions of the materials considered, the analysis by the present study reveals that the value of NB in ion-conducing polymers is about 5 times larger than that in metallic systems, and for each system, the material dependence of βKWW is clearly seen in the fragility index m and the cooperativity NB.

Diffusion in Metallic Glass-Forming Systems: A Description of the Kink Behavior Observed in the Temperature Dependence

“…Regarding the cooperativity of atomic dynamics in supercooled liquids, our analysis based on the Bond Strength-Coordination Number Fluctuation model [21] indicates that the number of structural units involved vary with temperature [22]. The connection of such a cooperativity with the fragility has been also investigated [23].…”

Network Relaxation and Cooperativity in Ion Conducting Polymers PEO-Li: An Analysis Based on the BSCNF Model

“…( 6) and ( 7), we obtain 𝑁 B = ln 10 𝑚 𝐶 ⁄ , that is, if we have the values of the fragility and the parameter 𝐶, we get information on the number of structural units that is involved in the cooperative movement. The above expression has been used to examine the cooperativity of various type of materials [24][25][26]. In particular, for the case of polymers, it has been found that 𝑁 B varies roughly between 20 and 80 [26].…”

“…The above expression has been used to examine the cooperativity of various type of materials [24][25][26]. In particular, for the case of polymers, it has been found that 𝑁 B varies roughly between 20 and 80 [26].…”