DIELECTRIC PROPERTIES OF INSULATING MATERIALS 511 



tion of relaxation-time t. The conductivity goes up as the dielectric 

 constant goes down, as if the one were being transformed into the other. 

 The most interesting feature of (18) is that as the frequency in- 

 creases 7' approaches a limiting value, and that this limiting value, 



o ♦ 



ORIENTATIONAL 

 OR BOUND ION 

 POLARIZATION 



OPTICAL 

 POLARIZATIONS 



I03T 



FREQUENCY, -^ 



Fig. 1 — Schematic diagram comparing the frequency dependence of dielectric 

 constant (e'), loss factor (e") and conductivity (7')- This applies to a polarization 

 having a single relaxation-time (r). The frequency in cycles per second is wllw. 



which will be designated as 700, has the value 



Too = 



eo — Ca 



Co — €» 



(20) 

 (20a) 



47r X 0.9 X lO^V ' 

 where (20) gives 7«, in e.s.u. and (20a) in ohm"^-cm~\ The con- 



