Variation of glass transition temperature with direction in unidirectional glass fiber-reinforced composites

Summary A theoretical expression of the value of the glass-transition temperatureT_g at any direction of orientation, defined by the angle subtended between this direction and the average axis of fibers; was introduced. Dilatometric, as well as dynamic tests were executed for a type of unidirectional composite in order to compare the respective values ofT_g derived from these tests. The experimental results were also compared with theoretical values derived from the theoretical expression. A satisfactory agreement between, theory and experiment was established.With 5 figures and 1 table