NON-EXTENSIVE VISCOELASTIC THEORY .6. APP LICATION TO A GLASS-FORMINGLIQUID - ORTHOTERPHENYL (OTP)

The non-extensive visco-elastic theory developed in articles (I-V) is tested using experimental data of a glass forming liquid, orthoterphen yl (OTP). This system has been widely studied during the last fifty ye ars. One obtains a coherent and rather simple description of a large n umber of these data, of statical, dynamical, thermodynamical and spect roscopical nature, if one supposes that the viscous phase between the melting temperature of the crystal and the glass transition temperatur e is a (quasi) simultaneous translational and rotational transition pr edicted by the theory, spread over this temperature range. The rather comprehensive analysis presented on this particular system, suggests t hat the theory is adequate to describe, in a unified manner, the main physical properties of liquids in their stable state between the boili ng temperature and the melting temperature of the crystal, and, when t hey can be supercooled, in their metastables states until very low tem peratures. In this latter situation, the description provides, among o ther things, a simple interpretation of the experimental features asso ciated with the so-called ''alpha relaxation'', ''beta relaxation'' an d ''boson peak''. It is suggested that spreading of the transition is to be associated with onset of spatial density fluctuations, transform ing the medium from homogeneous to inhomogeneous. The maximum local de nsity increases faster than the average density as temperature decreas es, and seems to level off at the conventional glass transition temper ature.