Inflatable device inflation assemblies wherein a gas source material is released from an inflator apparatus into an inflatable device wherein the gas source material may, such as upon actuation of an initiator device situated within the inflatable device, dissociate or otherwise form gaseous products for the inflation of the inflatable device. An inflatable restraint system is also provided which includes a plurality of inflatable devices each operatively joined with a chamber which contains a dissociative gas source material. The system includes at least one first initiator effective upon actuation to initiate dissociation of the gas source material within a selected one of the plurality of inflatable devices. A method for inflating an inflatable device is also provided wherein a quantity of at least one gas source material is released into the inflatable device and which gas source material, when initiated, undergoes dissociation to form dissociation products including at least one gaseous dissociation product.