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Vinyl-containingtitanium-silphenylene-sioxane oligomers(O1,O2,O3,andO4)withdifferent molar ratios of titanium to silicon were successfully synthesized in high yields by nonhydrolytic sol-gel reaction,and the obtained four oligomers were further crosslinked with methylphenyl hydro-silicone oil (4) to form corresponding polymers (P1,P2,P3,and P4) by hydrosilylation reaction.Their structures were characterized with spectroscopic characterization techniques including FTIR,1H-NMR,and Raman spectroscopy.The effect of titanium element on crosslinking behavior,thermal resistance,refractive index,transparency,thermal aging stability,glass transition temperature,and surface properties of the polymers were studied.Compared with titanium-free polymer P1,the thermal resistance,refractive index,and thermal aging stability of titanium-silphenylene-siloxane polymers (P2,P3,and P4) were significantly improved.The titanium-silphenylene-siloxane polymers achieved a high refractive index (n =1.580-1.584) and thermostability (Tsd ＞ 500 ℃).In thermal aging,the polymers exhibited superior performances with high optical transparency (～90％ at 450 nm) and exhibited high thermal stability (～84％ at 450 nm after thermal aging at 150 ℃ for 120 h).These data indicate that the polymers have potential application in optical materials such as LED encapsulants.