FABRICATION AND OPTICAL THERMAL PROPERTIES OF GLASS PARTICLE-EPOXY OPTICALLY TRANSPARENT COMPOSITES/

The possibility of fabricating a new type of optically transparent gla ss particle dispersed epoxy matrix composite by tailoring the refracti ve index of the particle and matrix was studied. Glass particles with an average diameter of approximate to 8 mu m were incorporated into a clear epoxy matrix and the particle volume fraction ranged from 0.01 t o 0.17. The refractive index difference after fabrication was less tha n 10(-3). The light transmittance of the composite in the UV-visible r egion and the coefficient of thermal expansion (CTE) of the composite were measured. The results demonstrated that the optically transparent composite was obtained with a lower CTE than the pure epoxy matrix. T he light transmittance of the composite decreased with increase in par ticle volume fraction, while the CTE of the composite showed an opposi te tendency. The light transmittance of the composite was explained th eoretically by a refractive index matching in the composite, which was different from that of the raw materials owing to thermal stress. (C) 1997 Acta Metallurgica Inc.