Interrelation of pyroelectric and nonlinear optical coefficients in ferroelectric crystals

An experimental relation is found between the pyroelectric and electrooptic coefficients of several ferroelectric materials. The physical basis of this relation is explained using Garrett's anharmonic oscillator model, and the pyroelectric coefficients of Sr
0.25
Ba
0.75
Nb
2
O
6
, Sr
2
NaNb
5
O
15
,Ba
2
NaNb
5
O
15
, KSr
2
Nb
5
O
15
, K
3
Li
2
- Nb
5
O
15
, and Ag
3
AsS
3
are predicted from the known electrooptic coefficients.