  Analysis of the thermo-mechanical behaviour of polymers has been and still is
the subject of many rheological studies both experimentally and theoretically.
For small deformations, the modelling framework retained by rheologists is
often of linear visco-elasticity, which led to the definition of complex
modules and used to identify the glass transition temperature as the so called
rule of time-temperature superposition. In this context, the effects of time
are almost unanimously associated with viscous effects. It has also been
observed that the dissipative effects associated with viscous effects are often
very small compared to the coupling of sources indicating a high sensitivity of
polymeric materials to temperature variations. This work is mainly focused on
establishing the exact role of coupling effects, which also induce the effect
of time. Using traditional experimental methods of visco-analysis (DMTA) and
via an energy analysis of the behaviour, the goal of the thesis is to try to
restate the time-temperature equivalence rule under the Thermodynamics of
Irreversible Processes, taking into account the dissipative effects and
coupling induced process deformation.
