An optically transparent woven glass fiber-reinforced polyester composite has been fabricated. This composite has been used as an interlayer in the fabrication of a laminated glass-composite window panel for application in blast-resistant windows. The transparency of the glass fiber-reinforced composite was achieved by matching the refractive index of the polyester matrix with that of glass fibers. Various chemical additives have been investigated for their effectiveness in modifying the refractive index of the polyester matrix. The composite interlayer's mechanical properties under both quasi-static and dynamic loading conditions have been characterized in this study. The window panels were tested under various blast loading conditions. The panels perform well under U.S. General Services Administration (GSA) specified C, D, and E blast loading levels.