Methoxy end groups were cleaved from poly[bis(methoxyalkoxy)phosphazenes] { [( 2-CH2)mOCH3]2}", where m = 2 (2, MEEP) and m -1 (3, MEP) by reaction with trimethylsilyl iodide to give silylated polymers {NP[(OCH2CH2)mOSiMe3L [(OCH2CH2)mOCH3]y}" (x + y = 2; m = 2 (4), m = 1 (5)). The silylated polymers 4 and 5 were hydrolyzed in a second step to yield the alcohol-functionalized polymers {NP[(OCH2CH2)mOH]z [(OCH2CH2)mOCH3]y}" (m = 2 (6), m = 1 (7)). The structures of both classes of compounds were investigated by 31P, 13C, and NMR and infrared spectroscopies. The correlation between the amount of ISiMes and the percentage of resultant alcohol functions was established. This latter was estimated by first using NMR and secondly 31P NMR. In the latter case use was made of the reaction of a bicyclophosphane 8 with the OH groups in 6 and 7, which leads to bicyclophosphorane-functionalized polymers. The two results are in agreement. The presence of the alcohol function was confirmed by the observation of cross-linking through the reactions of 6 and 7 with a diisocyanate and a polyphosphazene functionalized by succinic anhydride groups. This functionalization reaction induces chain degradation of the polymer as the percentage of alcohol functions increases.