Plot a function with an specific colour asociated to each data

I want to plot irradiaction data vs the exposure time, but I also want to assign an specific colour (described with RGB or CIELab parameters) to each value of irradiance.

Is there any way to plot irradiance vs time and create a fit associated with the color creating a custom colorbar? or at least, a plot with changing colour (ΔE* ) vs the irradiance but with the associated colorbar?

In order to calculate ΔE*, my reference colour value is the fist one, with is zero exposure.

ΔE* = ( ( L*1-L*2)2 + (a*1-a*2)2+(b*1-b*2)2 )1/2

Below I show the code with the graphs that I want to obtain, where it would be necessary to add the line colour.

clear all
clc

%Data
A=[88.83 -7.90 49.88 0 0
81.19  5.46 34.44 10.4 5
78.86  8.68 33.31 14.7 10
75.71 13.76 24.59 25.5 20
72.87 18.72 20.56 35.1 32
71.00 21.25 17.31 50.1 50];

L=A(:,1); %L*
a=A(:,2); %a*
b=A(:,3); %a*
I=A(:,4); %irradiance in mJ/cm2
t=A(:,5); %time in s


%Figure 1
figure (1)
plot(t,I)
xlabel('t (s)')
ylabel('I (mJ/cm^2)')


%Colour difference
for i=1:6
        DL_star=A(i,1)-A(1,1);
        Da_star=A(i,2)-A(1,2);
        Db_star=A(i,3)-A(1,3);
        DE_star(i)=sqrt((DL_star)^2+(Da_star)^2+(Db_star)^2);
end

%Graph of colour difference vs irradiance
figure(2)
plot(I,DE_star)
xlabel('I (mJ/cm^2)')
ylabel('\DeltaE')

Answer 1

[KSSV]

x = linspace(0,2*pi)' ;
y = sin(x) ;
z = y ; 
% Plot data:
surf([x x], [y y], [z z], 'FaceColor', 'none','EdgeColor', 'interp', 'LineWidth', 2);           
view(2);   
colormap(jet)
colorbar;  

[Beatriz]

Correct me if I'm wrong, but in this color bar, the color represents one of the variables already represented, in this case the variable y.

What I am looking for is to represent with color a variable z, which would be defined with three (RGB, or Lab)

[KSSV]

The RGB color bar represents the variation of y along the curve.

jet

ans = 256×3

0 0 0.5156 0 0 0.5312 0 0 0.5469 0 0 0.5625 0 0 0.5781 0 0 0.5938 0 0 0.6094 0 0 0.6250 0 0 0.6406 0 0 0.6562

[Beatriz]

But in your graph, the color does not add information, it only highlights the change of y that is already seen in the plot.

What I want is to represent a variation of z with the colour, not y. But I dont know if it is possible to link data colour (the three RGB data values) with a single colour bar.