STRUCTURAL CHARACTERIZATION OF HETEROCYCLIC POLYMER NETWORKS BY LOW-FREQUENCY RAMAN-SCATTERING

Glassy, heterocyclic copolymers of an epoxy oligomer and hexamethylene diisocyanate were characterized by low-frequency Raman scattering spe ctra at room temperature. The experimental data were treated according to the formalism of the theory of inelastic light scattering from fra ctons to derive structural information in the scale range below 10 nm. The samples studied were shown to behave essentially fractal-like in the range of characteristic scales (on an order-of-magnitude basis) sp anning roughly the chain persistence length (ca. 0.7 nm) as a lower st ructural limit and the network mesh size (ca. 3 nm) as an upper struct ural limit.