Bulk glasses PbxGe(42-x)Se(48)Te(10)(0less than or equal toxless than or equal to15) and Pb20GexSe70-xTe10(17less than or equal toxless than or equal to24) have been prepared by quenching the melt. The non-isothermal properties of these glasses have been determined using a Differential scanning calorimeter (DSC). The composition dependence of the glass transition temperature, crystallisation temperature, excess heat capacity at glass transition, glass forming tendency and activation energy of glass transition and crystallisation show anomalous features near the composition at which the p- to n-type transition occurs. These observations reflect the changes occurring in the chemical bonding and the nature of the glassy network in these glasses. The results have been interpreted in terms of existing models and the majority charge carrier reversal phenomenon occurring in these glasses. (C) 2003 Kluwer Academic Publishers.