Techniques of Ultrastructure Synthesis Relevant to the Fabrication of Electrooptic Modulators

Main-chain syndioregic nonlinear optical polymers. II. Extended pi conjugation and improved thermal properties

“…1 H NMR analysis showed very little cyclomer in the reaction mixture (about 5 times less cyclomer than when the polymerization was performed at 130°C) along with complete consumption of the active methylene protons, so 0.025 g (0.1 mmoles) more of the A-1 was added. The reaction was then allowed to continue for 7 more days at 90°C.…”

“…After 4 days the solution was precipitated in ethanol filtered, and dried to give 0.33 g (50%). 1 This material was found to contain a large amount of cyclomer (15%). The cyclomer appeared to be as soluble as the polymer in most solvents and it was very difficult to remove the cyclomer.…”

“…The solution was heated at reflux for 3 days under nitrogen, cooled to room temperature, precipitated into absolute ethanol, filtered and the polymer dried under vacuum to give an orange/yellow powder in 0.95 g (94%). 1 H NMR (CDCl 3 ): 6.64-8.05 (m, 14H); 3.52 (q, 4H); 1.13 (t, 6H)…”

“…This was chromatographed on Silica Gel using 5% MeOH/CHCl 3 to give 2.92 g of a yellow solid, 1,3-Phenylenediamine bis-acetoacetamide, (38%). 1 …”

“…These materials showed significant loss of the NLO signal due to relaxation of the chromophore well below the glass-transition temperature (T g ) of the polymer. Several approaches to stabilizing the NLO signal have been reported, [1][2][3] such as incorporating the chromophore as a side chain in the polymer, crosslinking, incorporating the chromophore into the main chain, either as head-to-tail, head-to-head, or mixed. We have been using the syndioregic approach to incorporate stability and ease of poling into a main-chain system.…”