We prepared several gas barrier resins based on amorphous PVA derivative that has the T1C (13C spin-lattice relaxation time) of a long time component in amorphous phase. We confirmed it was important to control state in amorphous phase of gas barrier resin in order to achieve both moldability and good gas barrier property. Polymer alloy was designed to improve flexibility. Polymer alloy made of amorphous PVA and elastomer resin showed good hydrogen resistance. Even after its polymer alloy were repeatedly exposed to 70MPa hydrogen gas, the influence on higher-order structure in amorphous phase was in negligible level.