Effect of pressure and temperature on chromophore reorientation in a side-chain nonlinear optical polymer

Effect of pressure and temperature on chromophore reorientation in a new syndioregic main‐chain hydrazone nonlinear optical polymer

“…The optical experimental details and in situ optical pressure cell are identical to our earlier experiments on guest-host and side-chain systems. 4,5 The synthesis and film preparation of SMCH ( Fig. 1) were previously reported.…”

“…This evaluation was made to verify that the bend in the plot of ln a p versus pressure is real and not an artifact of our fitting procedures. That analysis and discussion are given elsewhere 5…”

“…Using that technique, we studied the reorientation of chromophores in guest-host and side-chain poled polymers. 4,5 The U.S. Navy Research Department at the China Lake Weapons Division has investigated the development of main-chain NLO polymers for many years. 6 For a given chromophore, it has been discovered that the chemical structure of the polymer chain plays an important role in the degree of polar order that can be imparted to the chromophores by electric field poling.…”

“…We previously reported on a technique that monitors the second harmonic generation (SHG) of a poled polymer under the influence of external hydrostatic pressure. Using that technique, we studied the reorientation of chromophores in guest–host and side‐chain poled polymers 4, 5…”

Effect of Pressure during Poling on the Relaxation of a Guest−Host NLO Polymer

“…In our previous work using measurements of the decay of the second-order optical susceptibility in electric field poled nonlinear optical (NLO) polymers, [7][8][9][10] we observed that the application of pressure on previously poled samples increases the T g and retards the relaxation of the polymer. The applied pressure reduces the free volume to some degree, causing low-frequency molecular motion such as rotational transitions or longrange cooperative motions to be greatly suppressed since these molecular motions require relatively large free spaces for the rearrangement of several atoms.…”