The 22Na tracer diffusivity, and the electrical mobility of Na ions, in 3SiO2•Na2O glass were determined by using a modified Chemla technique. It was found that the Haven ratio was equal to 0.30 at temperatures of between 300 and 380C. The results (tables 121 and 122) suggested that an interstitialcy mechanism was operating and involved co-linear jumps rather than a vacancy process.

P.Laborde, C.Kaps, H.Kahnt, A.Feltz: Materials Research Bulletin, 1989, 24[8], 921-30

 

 

 

Table 121

Diffusivity of 22Na in 3SiO2•Na2O Glass

 

Method*

Temperature (C)

D (cm2/s)

C

299.5

7.82 x 10-10

E

299.5

2.19 x 10-9

C

302.0

7.67 x 10-10

E

302.0

2.34 x 10-9

C

349.1

2.21 x 10-9

E

349.1

6.91 x 10-9

C

350.0

2.52 x 10-9

E

350.0

7.80 x 10-9

C

380.0

3.92 x 10-8

E

380.0

1.27 x 10-9

C

382.0

5.06 x 10-8

E

382.0

1.56 x 10-9

*C: Chemla technique, E: deduced from Einstein equation

 

 

 

 

Table 122

Mobility of 22Na in 3SiO2•Na2O Glass

 

Temperature (C)

μ (cm2/Vs)

299.5

4.44 x 10-8

302.0

4.71 x 10-8

349.1

1.29 x 10-7

350.0

1.45 x 10-7

380.0

2.25 x 10-7

382.0

2.77 x 10-7