Series of niobate-phosphate and niobate-silicate glasses doped with Eu

3+

ions were prepared. The emission

phonon-side band spectra and fluorescence lifetimes of these glasses were studied and the intensity parameters Ω

2

of Eu

3+

were obtained. The temperature-dependence of emission intensity of the Eu

3+

-ion in these niobate glasses was investigated. The temperature-quenching rates were determined. The results indicate that in niobate glasses

as the concentration of Nb

2

O

5

increases

the covalence becomes strong

the symmetry becomes low and the electron-phonon coupling strength becomes strong

thus the lifetimes become short

the nonradiative transition processes and the temperature-quenching become strong. The temperature-dependent behavior of the Eu

3+

ion was studied in various niobate glasses. The variation of the emission intensity of Eu

3+

with temperature was attributed to two factors

the thermally excited emission from

7

F

2

to

5

D

2

and the temperature-quenching effect. The former tends to cause the intensity of Eu

3+

increase with temperature

while the later tends to cause the intensity decrease. The temperature-quenching rates in various glasses were obtained. They increase with the increasing concentration of Nb

2

O

5

. The temperature-dependencies of the peak energies and the line widths of

5

D

0

→

7

F

J

(

J

=0

1)were experimentally determined.