D. Horvat et J. Mozina, OPTICAL MONITORING OF THE SOLIDIFICATION PROCESS OF POLYESTER AND VINYL RESINS, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 173(1-2), 1993, pp. 181-184
Ultrasonic waves were generated and detected by laser light in solidif
ying polyester and vinyl resins, allowing an evaluation of the extent
of reaction by a non-contact method. Commercial polyester and vinyl re
sin samples were prepared following the standard procedure under room
conditions. A liquid adjacent to the sample was irradiated by a pulsed
Nd:YAG laser beam. The resulting ultrasonic wave was detected in the
sample at two distances from the source by the deflection of an He-Ne
laser probe beam. The displacements of the probe beam were detected by
a position-sensitive photodiode. Arrival times of the ultrasonic puls
es at various times during the solidification were measured and the co
rresponding propagation velocities calculated. The method is aimed at
monitoring the final part of the solidification, after the gelation ha
s taken place, and will allow the investigation of the influence of va
rious parameters on the course of the reaction and on the final proper
ties of the material.