The measurements of the laser damage thresholds of metal-coated plastics were performed. The results have shown that the plastics could be used as laser mirrors in pulsed devices. An optical quality of the varifocal plastic mirror is comparible with that of conventional massive mirrors and of the other complex varifocal mirrors. It has shown that mylar mirrors is stable and unstable cavities of the pulsed TEA C02-laser could replace the traditional massive mirrors. Simplicity of design and easy parambter variation of adaptive plastic mirrors are advantageous for using in different laser devices.