Time-resolved Raman spectroscopy is evaluated as a tool for studying reactions in aerosol microdroplets. As a test reaction, the absorption of D(2)O vapor by an optically levitated glycerol droplet is considered. With the present apparatus, time scales of the order of 1 s have been resolved. By considering the relative amplitude of various features, the composition of the suspended droplet can be estimated as a function of time. In addition, for the D(2)O-glycerol system the average temperature of the optically levitated droplet can be deduced.