We study cross-linking and pyrolysis behavior of Si(O)CN ceramic fibers prepared via hand-drawing and polymer pyrolysis of a 1,3,5-trimethyl-1,3,5-trivinyl-cyclotetrasilazane (1- 3- 5 TTCSZ) with polyacrylic acid (PAA) organic polymer as the spinning agent. This type of cyclic silazane oligomer is a precursor for polymer-derived silicon carbonitride or SiCN ceramic. Like other preceramic polymers for SiCN ceramics, 1-3-5-TTCSZ is not fiber spinnable in its pristine form due to either low viscosity, non-meltability after cross-linking, or molecular structure (cyclic rather than linear structure). The addition of PAA to TTCSZ remarkably improved spinnability of the silazane. Investigation of changes to the molecular structure of the precursor and chemical composition of the fibers at various stages of cross-linking and pyrolysis temperature was conducted via Raman spectroscopy, Fourier- Transform InfraRed spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), and Nuclear Magnetic Resonance (NMR) to establish the cross-linking and pyrolysis pathways of the fibers.