The influence of the sample specific surface on the crystallization kinetics of the Sb2S3 in Ge0.3Sb1.4S2.7 glass has been studied. It was found that the DSC crystallization data for the bulk sample can be described by the Johnson-Mehl-Avrami (JMA) model corresponding to three-dimensional crystal growth. The same description for powder samples is not possible and the empirical Sestak-Berggren equation had to be used. The condition of the validity for the JMA model is discussed.