Process for converting certain lactones to their alpha-methylene substituted forms in a supercritical or near-critical fluid phase reaction using an oxynitride catalyst or a composite oxynitride catalyst incorporating lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, or barium or combinations thereof. The disk drive further includes a spindle motor hub rotatably coupled to the disk drive base. Thus, the dopant profile is established from a horizontal direction, allowing the profile to be controlled.