Commercially available polyureamethylvinylsilazane (Ceraset, Kion Corporation, Huntington Valley, PA) and aluminum isopropoxide (Al(OCH(CH 3 ) 2 ) 3 ) (AIs, Alfa Aesar, Ward Hill, MA) were used as starting materials. Ceraset, as received, is a pale yellow liquid, and AIs is a white powder. Both materials were used as received without further purification. Figure 1 shows the chemical structure of Ceraset cited by the supplier 24-27 and confirmed by previous study. 28 The polyaluminasilazanes were prepared using the following procedure. First, AIs powders were dissolved in liquid Ceraset at room temperature while stirring magnetically. A small amount 2415 J ournal