A simple nondestructive evaluation of an adhesive layer using elastic wavevelocities

A curing process of epoxy adhesive layers has been investigated by an ultra sonic pulse spectroscopy and a Brillouin scattering technique. Observed lon gitudinal elastic wave velocities in the curing layer depended on the veloc ity in the prepolymer used. From this result, we suggest a simple nondestru ctive method for the estimation of sample T-g (glass transition temperature ) during cure. The estimated T-g values were in good accordance with the T- g values easured by differential scanning calorimetry.