This work investigates influence of boiling liquid on mechanical behavior of fiber reinforced polymers. R-134a used as pressure-liquefied gas at 273 K was boiled by instantaneous depressurization. A compressor was used to re-liquefy boil-off gas and to achieve a cyclic liquid-vapor condition. Specimens of glass fiber reinforced polymers (GFRP) were immersed in the cyclic condition. After immersion, micrographs showed microcrack development. short-beam three-point bending tests were performed. To evaluate the influence of the boiling condition on interlaminar shear strength of GFRP.