1,3,5,7,9,11,13,15-Octakis(dimethylsilyloxy)pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane; Poly(hydridosilsesquioxane)-polymeric T8 with all silicons dimethylsiloxy substituted; Poly(hydridosilsesquioxane); 1,3,5,7,9,11,13,15-octakis[(dimethylsilyl)oxy]pentacyclo[9.5.1.1~3,9~.1~5,15~.1~7,13~]octasiloxane