Synthesis of Poly(phenyl-o-tolylphosphazene) via Reaction of Trimethylsilyl Azide with 2,2,2-Trifluoroethyl Phenyl-o-tolylphosphiniteIn order to obtain the desired monomer 2, the initially synthesized phenyl-o-tolylchlorophosphine ( 1) is reacted with 2,2,2-trifluoroethanol in the presence of triethylamine.

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Optical data storage has become the mainstream technology during the past two decades for distributing audio, video, and software content as well as for recording and archiving personal data. The continuous demand for ever-higher storage capacities and faster data transfer has led to the development of three disc format families using infrared (compact discs), red (digital versatile discs), and blue lasers (Blu-ray discs or high-density DVDs). Substrate materials used in optical discs need to possess a complex property profile with sufficient optical, rheological, mechanical, and processing characteristics to ensure cost-efficient replication, good read/write performance, and long-term media stability. Bisphenol-A polycarbonate (BPA-PC) is the substrate material of choice and has undergone several optimization cycles to always meet new format specifications. Figure 1. Roadmap of optical data storage and its key parameters. CD compact disc, DVD digital versatile disc, HD-DVD high-definition digital versatile disc, BD Blu-ray disc, λ wavelength of the laser light, NA numerical aperture of the objective lens, and d thickness of substrate or cover layer. www.mrs.org/bulletin

Poly(dipheny1phosphazene) (PDPhP) was synthesized by a reaction of 2,2,2-trifluoroethyl diphenylphosphinite with trimethylsilyl azide. Characteristics of the polymer exhibit a marked molecular weight dependency. DSC measurements showed that the PDPhP undergoes a mesophase T(l) type transition in the range 180 -190 "C and another at 240 -255 "C depending upon the molecular weights of the polymers. Upon heating and cooling through T(1) the higher molecular weight PDPhP transforms to a 3D orthorhombic (y-form) with a = 1,99 nm, b = 1,05 nm and c = 0,995 nm from its original form (a-form) in which a = 1,Ol nm, b = 1,Ol nm and y = 101 after passing through the disordered mesophase (&form). Another 3D form (pform) with c = 1,25 nm is formed from the lower molecular weight PDPhP after heat treatment of the 2D phase (&form) that is obtained by quenching the specimens into ice-water (4°C) from above T(1). The conditions for the formation of the /3-form depend strongly on the polymer molecular weight and its history. Lath-shaped crystals were grown from dilute dicblorobenzene solution by adding p-xylene (a non-solvent). Electron diffraction patterns of solution grown PDPhP specimens exhibit unusual hexatic triple reflections associated with the mesophase. (100) twinning due to the thermal history of the specimens has been established. A complex (multistep) heat treatment process was required to elucidate the transformation behavior in PDPhP.

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