The pilot-in-command reported that during cruise at flight level 210 an intermittent acrid electrical burning smell was noted. Shortly afterwards a white flash occurred near the wiring terminals of the right forward windscreen. This was followed by a fire at the electrical terminals. Appropriate emergency drills were completed by the crew and a fire extinguisher was used to extinguish the fire. The windshield heat was switched off and a descent commenced. Passing flight level 130 on descent the outer windshield panels shattered. A safe landing was made into Melbourne. Maintenance found that the windscreen integral bus bar had overheated and ignited. The window is to be returned to the manufacturer for analysis. The windshield temperature controller was also changed as a precautionary measure.