Chemical hydrogels based on poly(vinyl alcohol), PVA, were obtained by reac
ting telechelic PVA bearing aldehydic groups at both ends of the chain with
the hydroxylic moiety of the polymer. These networks were studied by dynam
ic light scattering around the sol-gel transition threshold. The auto-corre
lation function, g((2))(q,t), displays nonergodic behavior when the system
enters the gel phase. Appropriate ensemble averaging of the g((2))(q,t) yie
lds the dynamic structure factor f(q,t). To extract from the f(q,t) the cha
racteristic parameters of the network, we adopted a model originally propos
ed for colloidal gels. A correct description of the f(q,t) was obtained. Th
e results were compared with those obtained independently on the same type
of hydrogels by equilibrium swelling and compression modulus measurements.
A link to macroscopic properties of the gels is also shown.