Title :
Acoustic phonons in an epoxy resin studied by Brillouin light scattering
Author :
Comez, L.D. ; Fioretto, D. ; Palmieri, L. ; Socito, G. ; Verdini, L.
Author_Institution :
Dipt. di Fisica, Perugia Univ., Italy
Abstract :
The elastic and viscoelastic properties of the epoxy system Epon 828 have been studied by means of the Brillouin light scattering (BLS) technique. The specimen, consisting of a transparent epoxy film supported by an opaque substrate, has been analyzed by means of a high contrast Fabry-Perot tandem interferometer. The characteristic frequency and lifetime of longitudinal and transverse acoustic modes have been measured in a wide temperature range, above and below the glass transition temperature Tg=257 K. From these data, the temperature behavior of both the teal and imaginary pair of the elastic moduli was obtained at the frequency of the Brillouin peak (≈10 GHz). Evidence is given of a very broad dispersion associated to both a structural and secondary relaxation. A full spectrum analysis has been also performed in order to determine the frequency dependence of the longitudinal elastic modulus
Keywords :
Brillouin spectra; elastic moduli; glass transition; phonon spectra; polymers; viscoelasticity; Brillouin light scattering; Epon 828; Fabry-Perot tandem interferometry; acoustic phonons; dispersion; elastic modulus; epoxy resin; glass transition temperature; opaque substrate; secondary relaxation; spectrum analysis; structural relaxation; transparent film; viscoelastic properties; Brillouin scattering; Elasticity; Epoxy resins; Fabry-Perot; Frequency; Light scattering; Phonons; Substrates; Temperature distribution; Viscosity;
Conference_Titel :
Ultrasonics Symposium, 1997. Proceedings., 1997 IEEE
Conference_Location :
Toronto, Ont.
Print_ISBN :
0-7803-4153-8
DOI :
10.1109/ULTSYM.1997.663120
