Patent ID: 6543931
Filing Date: 2003-04-08
Classification: G01N

Abstract:
A method of evaluating the glass-transition temperature of a polymer material during use, wherein the following stages are carried out:a) determining the glass-transition temperature of the polymer material in the initial state by means of a conventional method, b) bringing two electrodes into contact with a part made of polymer material in the initial state, c) setting up the relaxation chart of said part made of polymer material in the initial state by means of complex permittivity measurements obtained with said electrodes, d) determining a characteristic time of relaxation of the polymer material in the initial state by means of said chart and of the glass-transition temperature determined in stage a), e) setting up the relaxation chart of the same polymer material during use with the same method as in stage b) and c), f) determining the glass-transition temperature of the polymer material during use by means of the relaxation chart set up in stage e) and of the characteristic time determined in stage d).