7 Li NMR INVESTIGATIONS IN AMORPHOUS IONIC CONDUC-TOR Li 2 B 2 O 4

In order to understand the mechanism of the ionic conductivity enhancement during pre-crystallization process, we have performed 7 Li NMR investigations on amorphous ionic conductor Li 2 B 2 O 4 . The temperature dependence of 7 Li NMR spectra is studied. It is found that 7 Li NMR spectra in crystalline, amorphous samples and amorphous sample with small amounts of crystallites are very different from each other. An additional peak is observed to overlap 7 Li NMR absorption line on amorphous sample with small amounts of crystallites. This phenomenon is similar to that in LiCl (or LiI) containing dispersed secondphase particles. 7 Li NMR investigations on amorphous ionic conductor B 2 O 3 -0.7Li 2 O-0.7LiCl is also made, the results are similar to that mentioned above. It is concluded that they are all caused by the interfacial effect between amorphous matrix and the crystallites.