Glass order parameter

The ratio of the intensities of the cross-peaks and the diagonal peaks are related to the glass order parameter qEA... 

Line shape studies of 7Rb and deuteron NMR lines have thrown more light on the frustration in the system. Blinc et al.5 have shown clearly the measurement of second moment can be related to the Edwards-Anderson spin-glass order parameter in the glass phase. 

The Edwards-Anderson spin-glass order parameter is defined as32... 

For a ferromagnet the order parameter is the magnetization, while for antiferromagnets it is the sublattice magnetization. For spin glasses the magnetization is zero at all temperatures, and an appropriate order parameter was proposed by Edwards and Anderson [78] as the average value of the autocorrelation function... 

Appendix A. Objective Measures of Fragility and an Order Parameter for Glass Formation Acknowledgments References... 

APPENDIX A OBJECTIVE MEASURES OF FRAGILITY AND AN ORDER PARAMETER FOR GLASS FORMATION... 

These measures of transition susceptibility, extent of ordering, and transition breadth apply equally well to equilibrium polymerization and self-assembly as to glass formation. Thus, these measures offer a unified description of the characteristics of rounded transitions. The XgL Eq. (A3) is a susceptibility measure where L corresponds to the average cluster relative mass, the order parameter >1) describes the extent of conversion of particles to the cluster state, and the variance in L or >1) reflect the transition broadness [246]. 

Eq. (91) is quite similar in nature to the following equation which is derived for the glass transition, assuming the freezing-in of one ordering parameter ... 

In a further development of the above model, Kalospiros and Paulaitis [101] use the glass-transition temperature of the pure polymer to calibrate the value of the order parameter (fraction of holes in the lattice). This value is kept constant, even if a swelling agent is added to the system, so the glass transition-temperature depression induced by the SCF can be predicted. 

At low temperatures the bend in the V(T) curves indicates a glass transition. It is of interest, whether this transition can be described in analogy to amorphous polymers on the basis of the concept of using one internal order parameter and whether the liquid crystalline structure is maintained in the glassy state. This will be discussed in Chap. 2.3.4. 

There has been a wealth of activity based on the idea that glassy dynamics is due to some underlying thermodynamic transition [1-25], If a glass former shows a jump in some an appropriate order parameter without the evolution of latent heat, then such a system is said to exhibit a random first-order transition [94,95]. Models of this kind, which include the p-spin glasses [110], and the random energy model [111], do not have symmetry between states but do have quenched random long-range interactions and exhibit the so-called Kauzmann entropy crisis. 

The ordering parameter Fx/2 is defined as Fx/2 = 2 Tg/Tx/2 — 1, where Ti/2 is such that the relaxation time x(7)/2) = 10 6s. In deriving Eq. (2.49), VTF temperature dependence for relaxation time x(T) or shear viscosity r (7 ) was assumed, and it was further assumed that between lower and upper ends of the glass transition region, the relaxation time and shear viscosity changed by 2.3 orders of magnitude [37],... 

At low temperatures, the configuration space of glass-forming liquids partitions into exponentially large number of disjoint regions [82,83,156-160]. The Boltzmann weight for such a region is very small. Hence, it is difficult to formulate an order-parameter that labels the metastable states in a quantitative fashion. 

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