A spectroscopic study has been made of the association of the first three members of the dimethyl, methylvinyl, methylphenyl, and diphenyl series of poly (diorganosiloxane)-αω- diols. A detailed examination of intramolecular hydrogen bonding in the trisiloxane-1, 5-diols has provided useful data on the stereochemistry of these compounds. Valency deviation due to the gem-diphenyl groups has been proposed to explain the high intramolecular hydroxy ...