Changes in the discontinuous creep of a polymer composite brought on by weak stress and magnetic fields

Using precision interferometric methods, we were able to record changes in the characteristics of discontinuous creep of glassy polymers brought on by preliminary treatment with weak external fields. For the example of a polymer composite we have shown that the long-period application of small loads and a constant magnetic field greatly reduces the nonuniformity of the creep rate at large stresses, i.e., it decreases the suddenness of abrupt deformations. After separating the effects of the magnetic and force fields, we concluded that the effects resulting from not only stress but also magnetic fields have partially reversible character. Our data confirm that a constant magnetic field affects the local potential barriers that inhibit strain in nonmagnetic materials. (C) 1998 American Institute of Physics.