Wavefront OBJ Assimp addon transparency issue

I am using the following code to load and draw the 3d Model that can be seen at this link
https://poly.google.com/view/45E5MnBNVLX

#include "ofxAssimpModelLoader.h"

class ofApp : public ofBaseApp{
	public:
		ofxAssimpModelLoader model;
		ofEasyCam cam;
		ofLight	light1,light2;
		void setup();
		void draw();
}

void ofApp::setup(){
	ofBackground(255, 255, 255);
	ofSetVerticalSync(true);
	ofEnableDepthTest();
	model.loadModel("glass_normal.obj");
	light1.setPosition(0, 0, -10);
	light2.setPosition(0, -400, 500);


void ofApp::draw(){
	cam.begin();
	light1.enable();
	light2.enable();
	light1.draw();
	light2.draw();
	model.drawFaces();
	light1.disable();
	light2.disable();
	cam.end();
}

I want the rendering to be similar to as seen on the chrome browser.
The lenses are not transparent. I have tried alpha blending that is not working.