We　present　the　first　demonstration　of　visible　emission　from　highly　doped　silica　glass　micro-ring　resonators　(MRRs)　through　a　third-harmonic　generation　(THG)　nonlinear　process.　We　obtain　green　light　conversion　efficiency　of　2.7x10(-5)　W-2　in　a　MRR　with　loaded　Q-factor　of　1.4x10(6)　pumped　in　the　telecom　band.　A　thermal　nonlinear　model　is　developed　to　account　for　the　in-cavity　power　dependence　of　the　resonance　detuning.　Using　the　extracted　thermal　nonlinear　coefficients,　the　measured　TH　resonance　shift　is　calibrated　by　subtracting　the　thermal　nonlinear-induced　phase　mismatch　to　obtain　the　theoretical　threefold　wavelength　relationship　along　with　the　measured　cubic　power　relationship.　(C)　2020　Optical　Society　of　America　under　the　terms　of　the　OSA　Open　Access　Publishing　Agreement