La-and Nb-doped BaTi2Q5 (BT2) spherical glasses were prepared by a containerless aerodynamic levita-tion method and their glass-forming regions were established.It is found that La-doping on the Ba-site(network-modifier) and Nb-doping on the Ti-site (network-former) show distinct difference in the glass-forming region:less than 10 ％ La can replace Ba whereas 40 ％ Nb can incorporate into BT2 glass.The distinction in glass-forming ability induced by La-and Nb-doping is discussed mainly from the struc-tural arrangement of the glass.Raman spectroscopy analysis shows that La-doping elongates the short Ti-O bonds in the distorted[TiOs]polyhedra and thus relaxes the network.Nb-doping introduces[NbO6]polyhedra into BT2 and there exists a critical doping level (20 ％),below which incorporation of Nb into BT2 relaxes the[TiOn]polyhedra by shortening the long Ti-O bond and above which[NbO6]starts to participate in the network skeleton construction resulting in a dramatic change in the glass structure,which is supported by the dramatic change in the exothermic peak on the DTA curves.This work triggers the speculation that the network-modifiers in BT2 glass possess a very important role in the structure of network-former skeleton than those in glasses based on traditional network-former oxides such as SiO2,GeO2 and B2O3,which may provide a useful strategy for modifying the properties of these novel glasses by chemical doping.