In one general embodiment, the material comprises a heat-stable polymer matrix having dissolved therein, thermally stable guest dipolar molecules, such as the acceptor-donor-acceptor molecule above, or a donor-acceptor-donor molecule of the general form: ##STR3## wherein X is O, S, CH2, or NR, where R is a lower alkyl group; and R1 and R2 are either fused ring structures having a ring-contained te