Vinylidene bromide (VDBr，M1) was copolymerized with different comonomers (M2)，including methyl acrylate (MA)，methyl methacrylate (MMA) and styrene (St)．The influences of properties and sequence distributions of the resulting eopolymers on the UV sensitivity of the recording materials have been investigated．It has been shown that UV sensitivity is the highest for eopolymer cotaining St and lowest for that con-taining MA．For recording materials prepared from same eopolymer，their UV sensi-tivity are related to the sequence distribution of the copolymer，especially P2(M1M2)．The reactivity ratios (r) of different monomers in the free radical copolymerization of VDBr with MA，MMA and St at 55土0.2℃，by using AIBN as initiator，were deter-mined

i.e. for VDBr-MA，r=0.72土0.05，r2=0.72士0.05；VDBr-MMA，r1=0.50±0.04．r2=1.74土0.04；VDBr．St，r1=0.4±0.04，r2=1.12士0.04．